WO2005019121A1 - Method and apparatus for treating organic waste - Google Patents

Abstract

A method for biologically treating an organic waste, characterized in that it comprises nitrifying the organic waste, followed by denitrification, and then solubilizing the sludge generated by the nitrification and the denitrification treatments; and an apparatus for biologically treating an organic waste, characterized in that it has means for nitrifying an organic waste, followed by denitrification, and for solubilizing the sludge generated by the nitrificaton and the denitrification treatments. The method can be used for biologically treating an organic waste from a sewage drain, feces and urine, or a production process in a food factory, a chemical plant or the like, and allows the marked reduction of the amount of excess sludge discharged out of a treating system and the decrease of the content of nitrogen-containing organic or inorganic components in a treated water discharged out of the treating system.

Description

 Description--------------------------------------------off--off; The present invention relates to a method and an apparatus for treatment by biological digestion. Background Art Conventionally, as a method of treating this kind of organic wastewater, an organic sludge is treated by an aerobic or anaerobic microbial decomposition such as an aerobic digestion method called an activated sludge method or an anaerobic methane digestion method. A method of biologically digesting organic components has been adopted. In this method, organic matter is converted into gaseous components such as carbon dioxide gas and gaseous gas, and treated sludge, including microbial biomass generated by biological digestion and excess sludge consisting of untreated residual sludge, is solid-liquid separated in a sedimentation tank. Excess sludge is usually treated by ocean dumping or land reclamation while the treatment liquid is appropriately treated by separation.

 However, dumping into the ocean will also lead to environmental destruction, and in the current era of global environmental protection, it is almost banned. In land reclamation, it is becoming more difficult every year to secure landfill sites.

 Accordingly, the present applicant filed a patent application for the method described in Japanese Patent Application Laid-Open No. Hei 9-110791 as a method for reducing the amount of excess sludge generated by biological treatment of organic wastewater. are doing.

According to the present invention, an organic waste liquid sent from an organic waste liquid storage device is subjected to aerobic biological treatment by an aeration device, and then the treated liquid is solid-liquid separated into treated water and sludge by a solid-liquid separation device. A part of the sludge separated by the liquid separator is returned to the aeration device and separated by the solid-liquid separator. In this method, excess sludge is heat-exchanged in a heat exchanger, then solubilized at a high temperature in a solubilizer, and the solubilized processing liquid is returned to the aeration device.

 However, since sludge generated by biological treatment generally contains protein, nitrogen compounds such as ammonia in the liquid returned from the solubilization unit to the aeration unit are discharged from the solid-liquid separation unit. There is a problem that it is released outside with water. In addition, since sludge generated by biological treatment generally contains phosphorus components, phosphorus compounds in the liquid returned from the solubilization unit to the aeration unit are discharged to the outside together with the treated water discharged from the solid-liquid separation unit. There is a problem of being released. DISCLOSURE OF THE INVENTION The present invention has been made in order to solve such a problem, and it is possible to significantly reduce the amount of excess sludge discharged to the outside of the treatment system and to release the excess sludge to the outside of the treatment system. It is an object of the present invention to provide a method and an apparatus for treating organic wastewater in which the content of nitrogen-containing organic or inorganic nitrogen in the treated water is reduced.

 In order to achieve the above object, the present invention provides a method for biologically treating organic wastewater, which is produced by nitrifying and denitrifying organic wastewater and then nitrifying and denitrifying the wastewater. An object of the present invention is to provide a method for treating organic wastewater that solubilizes sludge.

 The present invention is also 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. The present invention provides a method for treating organic wastewater.

 As described above, according to the present invention, the organic wastewater is subjected to nitrification and denitrification, and then the sludge generated by the nitrification and denitrification is dissolved. This has the effect of reducing the amount of nitrogen-containing organic components and nitrogen-containing inorganic components in the treated water released outside the treatment system as compared with the conventional case. The nitrification and denitrification treatment of organic wastewater is performed, for example, batchwise in a reaction tank.

The nitrification treatment in this case is performed, for example, by aeration, and denitrification by stopping the aeration. Processing is performed. Returning the solubilized solution to the reaction tank is preferably performed 3 hours to 30 minutes before stopping the aeration, and more preferably 1 hour to 30 minutes.

 If the nitrification and denitrification treatment is performed in a batch system including the nitrification step by aeration, and the solubilization solution is returned to the reaction tank a predetermined time before the aeration is stopped, it is included in the solubilization treatment sludge. The denitrification can be promoted by effectively utilizing the organic matter obtained as a proton source (BOD source) in the denitrification treatment. Therefore, the amount of chemicals such as methanol generally used as a proton source can be reduced, and the cost associated with the amount of chemicals can be reduced.

 Another aspect of 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 anoxic tank, and a secondary aeration step. In this case, the sludge solid-liquid separated after the secondary aeration step is solubilized.

 Further, other aspects of the nitrification and denitrification treatment of organic wastewater include 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 step. Done. In this case, the sludge separated into solid and liquid after the aeration step is solubilized. Nitrification is performed in the aeration process, and the nitrified liquid after nitrification is returned to the denitrification process. Further, other aspects of the nitrification and denitrification treatment of the organic wastewater are carried out by an anaerobic treatment step, a denitrification step in an anoxic tank, and an aeration step, and reduce the dissolved oxygen of the treatment liquid after the solubilization treatment. It is done by things. Also in this case, nitrification is performed in the aeration step. The nitrified liquid after nitrification is returned to the denitrification process.

 Further, other aspects of the nitrification and denitrification treatment of the organic wastewater are performed by an anaerobic treatment step, a denitrification step in an anoxic tank, and an aeration step.

 When these nitrification and denitrification treatments include an aerobic treatment step such as an anaerobic treatment step or an aeration treatment, even when the sludge generated by the nitrification and denitrification treatment contains a phosphorus component, However, phosphorus is released by anaerobic treatment, and phosphorus is taken up by aerobic treatment.

Another object of the present invention is to reduce the amount of phosphorus components in treated water released outside the treatment system. And a method of treating such organic wastewater.

 In order to achieve such an object, the present invention provides a method and an apparatus for treating organic wastewater provided with a means for removing phosphorus in sludge generated by nitrification and denitrification as described above. I do. By providing such a phosphorus removing means, there is an effect that discharge of the phosphorus component out of the system can be suitably prevented. 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 step performed by the processing apparatus of FIG.

 FIG. 3 is a block diagram of another example of a batch processing step performed by the processing apparatus of FIG. 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 of another embodiment. FIG. 6 is a schematic block diagram showing an organic wastewater treatment apparatus of 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 of 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 of another embodiment. FIG. 11 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 12 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 13 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 14 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 15 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 16 is a block diagram of a batch processing step performed by the processing apparatus of FIG.

FIG. 17 is a schematic block diagram showing an organic wastewater treatment apparatus of another embodiment. FIG. 18 is a schematic block diagram showing an organic wastewater treatment apparatus according to another embodiment. BEST MODE FOR CARRYING OUT 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, the organic wastewater is treated batchwise. In this embodiment, sewage was used as the organic wastewater as raw water.

 In the present embodiment, the treatment is performed in such a manner that the inflow, the reaction, the sedimentation, the drainage, and the sludge of the raw water are included in one cycle. More specifically, as shown in Fig. 2, the process of aeration, agitation, aeration, agitation, aeration, sedimentation by stopping aeration, solid-liquid separation, and solubilization treatment is performed while receiving the inflow of raw water. become. In this case, aeration is an aerobic treatment and agitation is an anaerobic treatment. The steps of repeating aeration and erosion, precipitation, and solid-liquid separation are performed in the reaction tank 1, and the step of solubilization is performed in the solubilization tank 2. It is possible to adjust the processing time of each process so that a series of wastewater treatments, from the inflow of raw water to the discharge of treated water, is performed several times a day (for example, two to four times). Depending on the properties and amount of the wastewater, the treatment time of each process may be adjusted so as to perform batch treatment about once a day or about twice a day.

 In the present embodiment, the nitrification treatment by the nitrifying bacteria is performed in the aeration step, and the denitrification treatment by the denitrifying bacteria is performed in the stirring step in which the aeration is stopped. Thereafter, the aeration is stopped, and the sludge is settled and separated. The supernatant is discharged, and a part of the settled sludge is held in the reaction tank 1 for the next batch processing, and the remaining part of the sludge is supplied to the solubilization tank 2 to be subjected to fusible treatment. . It is preferable that the liquid solubilized in the solubilization tank 2 is returned to the first-stage stirring step as shown in FIG. In the nitrification step, the pH is preferably set to 7 or more, particularly preferably 7.0 to 8.0, in order to maintain the nitrification reaction by the nitrifying bacteria. Further, the temperature is preferably 15 ° C. to 35 ° C., and more preferably 25 ° C. to 35 ° C.

The solubilized solution should be used 3 to 30 minutes before stopping the first stage aeration, preferably 1 hour to 30 minutes before being returned to reaction tank 1. The number of cycles is determined by the BOD-SS load of the reactor. Generally, in the case of high-load operation (800-33 load: 0.2-0.41¾80 D / kgSS-day), it is preferable to operate the nitrification and denitrification treatment cycle of aeration and stirring in three to four cycles. In the case of low load operation (BOD-SS load: 0.03 to 0.05 kgBOD kgSS-day), it is preferable to operate the nitrification and denitrification treatment cycle in 2 to 3 cycles.

 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 a protease. This solubilizing enzyme is produced by a thermophilic bacterium, for example, an aerobic thermophilic bacterium such as a bacterium belonging to the genus Bacillus. Such a thermophilic bacterium may be held in the solubilization tank 2 in advance, may be contained in the sludge supplied to the solubilization tank 2 in advance, or may be newly added in the solubilization tank 2.

 Examples of Bacillus bacteria include Bacillus stearothermopilus J, Bacillus thermole QYorans, and Bacillus thermole QYorans. In particular, Bacillus (Badllii5) can be used. ) SPT2-l (FERM P-15 395), Bacillus (Eaemii_s) SPT3 (FERM P-19226), Dionocylus (Geobac) P-08453], Geobacillus (Geobadllus) SPT6 [FERM P-08454], Geobacillus (Geobaci11us) SPT7 [FERM P-08455] and the like are preferably used.

 In the solubilization tank 2, sludge is decomposed by the thermophilic bacterium as described above. However, ozone decomposition, electrolysis, thermoalkali decomposition, and enzymatic decomposition (for example, proteases, lipases, glycosidases, etc. are used alone) Or addition in combination) may be carried out in combination with conventionally known various methods.

In the solubilization tank 2, the organic sludge is anaerobically or aerobically solubilized under biologically high temperature conditions. In this case, inoculated cells (thermophilic bacteria) of anaerobic or aerobic microorganisms used in high-temperature conditions are, for example, obtained from a conventional anaerobic or aerobic digestion tank. It is obtained by culturing an organism. The optimum temperature of the fusible tank 2 is preferably operated under the condition of a temperature range of 50 to 90 ° C., but the organic solid contained in the sludge to be subjected to the high temperature treatment is preferably used. It depends on the type of thermophile that decomposes substances.For example, in the case of thermophiles isolated from excess sewage sludge, the solubilization reaction of microorganisms (thermophilic bacteria) and physicochemical pyrolysis by heat The temperature at elevated temperature is in the range 55-75 ° C, preferably 60-70 ° C, so that both actions can take place efficiently and satisfactorily.

 In any case, depending on the type of microorganism, 50 to 90 so that both the solubilization reaction by the microorganism (thermophilic bacterium) and the physicochemical thermal decomposition by heat can be generated efficiently and sufficiently simultaneously. It is desirable to set the temperature to be in a temperature range of ° C. In particular, when a Bacillus bacterium, which is an aerobic thermophilic bacterium, is used, the temperature is preferably set to 55 to 70 ° C, more preferably 60 to 65 ° C. In addition, when using a bacterium belonging to the genus Diobacillus, which is an aerobic thermophilic bacterium, the temperature is preferably set to 55 to 65 ° C.

 The pH is set so as to be in the range of 6 to 9, preferably 7 to 8, depending on the type of microorganism. This is to prevent the soluble solution from affecting the nitrification or denitrification. Further, the solubilization treatment is preferably an aerobic treatment in order to decompose (nitrify) ammonia generated by the decomposition of sludge to some extent. In the present embodiment, the solubilized sludge is returned to the reaction tank in the first (first) aeration process 3 hours to 30 minutes before, preferably 1 hour to 30 minutes before stopping the aeration process. You. As a result, the organic matter contained in the solubilized sludge can be effectively used as a proton source (BOD source) in the denitrification treatment, and the denitrification can be promoted. Therefore, the amount of chemicals such as methanol generally used as a proton source can be reduced, so that 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 time is determined by the combination of the wastewater treatment system for nitrification and denitrification of wastewater and the solubilization of sludge. A description will be given for each embodiment.

 In addition, ammonia is generated by solubilization of sludge by thermophilic bacteria.Ammonia contained in solubilized sludge is oxidized to nitrite nitrogen and nitrate nitrogen that can be denitrified in the aeration process. It becomes. As a result, the denitrification treatment is suitably performed, and no harmful nitrogen components are released outside the system.

 In this embodiment, in the aeration step, it is important to oxidize ammonia to nitrous acid and nitric acid while leaving organic matter, so that the solubilized sludge is returned to the reaction tank in the first aeration step. It is important to set the timing and the solubilization time. (Embodiment 2)

 This embodiment is a batch-type treatment method similar to the first embodiment, in which the treatment apparatus is composed of a reaction tank 1 and a soluble ibis tank 2, and aeration is performed while receiving the inflow of raw water. Embodiment 1 is common to Embodiment 1 in that the steps of stirring, aeration, stirring, aeration, precipitation by stopping aeration, solid-liquid separation, and solubilization are performed in a circulating manner. Therefore, also in the present embodiment, nitrification treatment by nitrifying bacteria is performed in the aeration step, and denitrification treatment by denitrifying bacteria is performed in the stirring step in which the aeration is stopped.

 However, in the present embodiment, as shown in FIG. 3, in the case of the first embodiment in which the treatment liquid after the solubilization treatment is returned to the first (first) stirring step, and is returned to the aeration step at this point. Is different.

 Also in this embodiment, since the solubilized solution is returned to the reaction tank 1 in the denitrification process, the organic matter contained in the solubilized solution is effectively used as a proton source in the denitrification process, and the denitrification is promoted. Is done. In this case, in order to reduce the ammonia contained in the treated sludge, it is preferable to oxidize to nitrite nitrogen or nitrate nitrogen which can be denitrified in the solubilization treatment. It is conceivable that the solubilization time is longer than in Embodiment 1, and is preferably 24 to 72 hours, more preferably 36 to 72 hours.

In particular, in this embodiment, since the organic matter as the proton source is directly returned to the denitrification treatment step, the amount of commonly used chemicals such as methanol can be reduced. There is an effect that the cost associated with the amount of the chemical can be reduced. As described above, the amount of excess sludge generated can be significantly reduced by combining sludge-soluble treatment with nitrification and denitrification treatment of wastewater, and by optimally setting the conditions of each treatment step when combined. There is an effect that the water quality can be reduced and the quality of the treated water can be maintained well. As the microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus (; Bacillus ^ bacterium ゃ ォ バ ゃ チ ル Bacillus (fieohae ilks) bacterium used in the first embodiment is used. Is preferred.

 Further, the temperature for the solubilization treatment is preferably in a temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Also, the pH at the time of the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.

 In addition, the temperature, pH, and the like in the nitrification step are the same as those in the first embodiment.

 (Embodiment 3)

 As shown in Fig. 4, the organic wastewater treatment apparatus of the present 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 sedimentation tank 8, And a solubilization tank 2. In the present embodiment, as the liquid to be treated stored in the fermentation liquid storage tank 3, an acid fermentation liquid obtained by gas decomposition (methane fermentation) of fermented rice discharged from a food factory or the like and fermenting is used. Sewage and the like are supplied to the anaerobic tank separately from the liquid to be treated.

 The anaerobic tank 4 anaerobically decontaminates the sewage and the acid fermentation liquor supplied from the fermentation liquor storage tank 1 and returns sludge when phosphorus is contained in returned sludge or acid fermentation liquor. It has a function of releasing phosphorus in the liquid.

The primary aeration tank 5 aerobically biologically treats the treatment liquid subjected to the anaerobic treatment in the anaerobic tank 4 by aeration and agitation, and oxidatively decomposes organic substances in the anaerobic treatment water or nitrifies the inflow ammonia. It is for. This primary aeration tank 5 is basically equipped with aeration means. The aeration means is not limited, but for example, an air diffuser can be used. The aeration is preferably carried out to allow aerobic digestion and degradation.

It is carried out at room temperature with a ventilation of 0.1 to 0.5 v vm, but depending on the load, it may be processed at a higher ventilation with a higher ventilation. The liquid to be treated is preferably adjusted to pH 5.0 to 8.0, more preferably adjusted to pH 7.0 to 8.0.

 The anoxic tank 6 is used for denitrifying the treatment liquid that has been aerobically treated in the primary aeration tank 5.

 The secondary aeration tank 7 is for aerobic biological treatment of 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 stirring. In this case, the secondary aeration tank 7 has both functions of nitrification and BOD removal. Then, although not shown, a part of the nitrification liquid, which is a treatment liquid in the secondary aeration tank 7, is returned to the oxygen-free tank 6, and nitric acid or nitrous acid in the nitrification liquid is denitrified.

 The sedimentation tank 8 is for solid-liquid separation of the treatment liquid biologically treated in the secondary aeration tank 7, and the separated liquid is reused or discharged as a treatment liquid, and the separated and precipitated solid is separated. A part of the sludge is supplied to the next solubilization tank 2 and the remaining part is returned to the anaerobic tank 4.

 Next, an embodiment of a processing method for processing both sewage and sewage discharged from a food factory or the like by the processing apparatus having the above configuration will be described.

First of all, the leftovers discharged from food factories are decomposed by gas. This gas decomposition is performed, for example, by acid fermentation and methane fermentation. An acid fermentation solution is obtained by such gas decomposition, and the acid fermentation solution is stored in the fermentation solution storage tank 3. From this fermentation liquid storage tank 3, the acid fermentation liquid is supplied to the anaerobic tank 4. Sewage is also supplied to the anaerobic tank 4. 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 agitated. The nitrification treatment is performed by the aerobic treatment by the aeration and stirring. Next, the treatment liquid aerated in the primary aeration tank 5 is supplied to the oxygen-free tank 6. In the anoxic tank 6, a denitrification treatment is performed.

 Further, the acid fermentation liquid is supplied from the fermentation liquid storage tank 3 to the oxygen-free tank 6. This is because the acid fermentation solution is effectively used as a proton source (BOD source) during denitrification and promotes denitrification.

 The treatment liquid denitrified in the oxygen-free tank 6 is supplied to the secondary aeration tank 7, where it is aerobically treated while being aerated and agitated. By the aeration treatment in the secondary aeration tank 7, nitrification is performed, and B〇D removal is performed.

 Next, the treatment liquid that has been aerated in the secondary aeration tank 7 is supplied to the precipitation tank 8. In the settling tank 8, solid-liquid separation is performed, and the separated liquid is reused or discharged as a treatment liquid, and part of the separated and precipitated solid sludge is supplied to the solubilization tank 2. The sludge is aerobically solubilized by thermophilic bacteria.

 The remaining part of the settled sludge is returned to the anaerobic tank 4 as returned sludge. The sludge solubilized in the solubilization tank 2 is returned to the anoxic tank 6 and processed again. Then, the denitrification treatment in the oxygen-free tank 6, the aeration treatment in the secondary aeration tank 7, the solid-liquid separation in the precipitation tank 8, and the solubilization treatment in the solubilization tank 2 are circulated and repeated. In the present embodiment, the sludge is solubilized in a continuous manner, not in a batch manner as in Embodiment 1 described above. HRT is required based on the effective capacity of That is, HRT can be calculated based on the following equation: HRT (hydraulic residence time) = V / Q (V: reaction tank volume, Q: influent volume).

 It goes without saying that as long as the desired degree of solubilization is achieved, the volume of the reaction vessel can be reduced as the HRT is shortened. Therefore, by determining the solubilization time based on the HRT, redundant solubilization processing is avoided.

Preferably, the HRT is selected based on the HRT that maximizes the production and secretion of thermophiles. By setting the HRT in this way, the generated and secreted sludge solubilizing enzymes Elemental reactions can be used efficiently. Normally, the HRT is preferably set to 12 to 72 hours, and more preferably set to 24 to 72 hours from the viewpoint of oxidizing the ammonia in the solubilizing solution. From the viewpoint of maintaining both of the quality of treated water, it is most preferable to set the time to 36 to 48 hours.

 HRT of tanks other than solubilization tank 2 is 0.5 to 1.5 hours in anaerobic tank 4, 2 to 6 hours in primary aeration tank 5, 0.5 to 3 hours in oxygen-free tank 6, and 0.5 to 1.5 hours in secondary aeration tank 7. 2 hours, preferably 0.5 to 1 hour in the anaerobic tank 4, 3 to 5 hours in the first primary aeration tank 5, 1-2 hours in the oxygen-free tank 6, and 0.5 to 1.5 hours in the secondary aeration tank 7.

 As the microorganism that produces a solubilizing enzyme for solubilizing sludge, thermophilic bacteria, in particular, various Bacillus (Eadllus) genus bacteria disclosed in Embodiment 1 and ゃ ゃ obacillus (Qeohae illiis) genus bacteria may be used. Is preferred.

 Further, the temperature for the solubilization treatment is preferably in a temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the fusibility treatment is also set to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 In addition, the temperature, pH, and the like in the nitrification step are the same as those in the first embodiment.

 (Embodiment 4)

 In the present embodiment, as shown in FIG. 5, a concentrator 9 is provided between the sedimentation tank 8 and the solubilization tank 2, that is, in the flow path from the sedimentation tank 8 to the solubilization tank 2.

In the present embodiment, the sludge separated in the sedimentation tank 8 is supplied to the concentrator 9. In the concentrator 9, the sludge is concentrated by, for example, gravity settling. As the concentration method, besides gravity sedimentation, flotation concentration, evaporation concentration, membrane concentration, addition of a flocculant, drum screen type concentration, or concentration method using centrifugal force can also be adopted. The sludge concentration rate is preferably from 99% by weight or less (sludge concentration of 1% by weight or more) from the viewpoint of improving the solubilization rate of thermophilic bacteria and making the solubilization tank compact. The concentrated solution after concentration is acceptable It is supplied to the solubilization tank 2. However, it is preferable that the sludge concentration does not exceed 5% by weight.

 If the content exceeds 5% by weight, it becomes difficult to send out by a pump, and sludge foaming due to aerobic treatment in the solubilization tank becomes remarkable.

 Anaerobic treatment in anaerobic tank 4, aeration treatment in primary aeration tank 5, denitrification treatment in anoxic tank 6, aeration treatment in secondary aeration tank 7, solid-liquid separation in sedimentation tank 8, solubilization tank 2 The solubilization process in is the same as in the third embodiment, and a description thereof will be omitted.

 As the microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus genus bacteria disclosed in Embodiment 1 and ォ バ obacillus (Oobacillus) bacterium are used. Is preferred.

 Further, the temperature at the time of the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is in the range of pH 6 to 9 as in the first embodiment, preferably? Set so that it is in the range of ~ 8.

 (Embodiment 5)

 In the present embodiment, as shown in FIG. 6, a nitrification tank 10 is provided between the fusible tank 2 and the oxygen-free tank 6, that is, in the return flow path from the fusible tank 2 to the oxygen-free tank 6. Has been. By providing such a nitrification tank 10, the ammonia contained in the sludge-soluble solution changes to nitrous acid or nitric acid.

 Further, in the present embodiment, a part of the sludge is returned from the settling tank 8 to the anaerobic tank 4, and the remaining sludge is also supplied to the nitrification tank 10 via the solubilizing tank 2.

In the present embodiment, the HRT of the solubilization tank is preferably selected based on the HRT that maximizes the production and secretion of the sludge solubilizing enzyme secreted by the thermophile. By setting the HRT in this way, the reaction of the generated and secreted sludge solubilizing enzymes can be used efficiently. Normally, the HRT is set to 12 to 72 hours, but in this embodiment, since the nitrification tank 10 is provided at the subsequent stage of the solubilization tank, the solubilization treatment liquid is in a state where ammonia remains in the solubilization treatment liquid. Can be put into the nitrification tank 10, and considering this, the HRT is more preferably set to 18 to 48 hours, and most preferably set to 20 to 36 hours.

 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 in the nitrification tank 10 must oxidize the ammonia contained in the sludge solubilization solution to nitrous acid and nitric acid, and it is necessary to leave organic substances that serve as proton sources in the next step of denitrification. Considering a certain point, the time is preferably set to 30 minutes to 3 hours.

 Anaerobic treatment in anaerobic tank 4, aeration treatment in primary aeration tank 5, denitrification treatment in anoxic tank 6, aeration treatment in secondary aeration tank 7, solid-liquid separation in sedimentation tank 8, fusible Since the solubilization treatment in the tank 2 is the same as that in the third embodiment, the description is omitted.

 As the microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus ^ Bacillus ^) bacteria disclosed in Embodiment 1, ゃ diobacillus (Qeohae illus) bacteria are used. Is preferred.

 Further, the temperature for the solubilization treatment is preferably in a temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, 55 The temperature is preferably set to a temperature in the range of 70 to 70 ° C, more preferably in the range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is also set in the same manner as in the first embodiment: H is set to be in the range of 6 to 9, preferably 7 to 8.

 (Embodiment 6)

 In this embodiment, two anoxic tanks are provided, and only one aeration tank is provided. This is different from the third to fifth embodiments.

 That is, as shown in FIG. 7, the processing apparatus of the present embodiment comprises a front oxygen-free tank 11, an anaerobic tank 4, a compatible tank 12, an oxygen-free tank 6, an aeration tank 13, a sedimentation tank 8, a concentrator 9, and a A soaking tank 2 is provided.

 In the present embodiment, the raw water flowing into the anaerobic tank 4 is supplied to the compatible tank 12.

The compatibility tank 12 has a function of changing the return route of the sludge and the treatment liquid (nitrification liquid) from the aeration tank 13 depending on the degree of denitrification of the inflow sewage. For example, the degree of denitrification in summer etc. During periods of high levels, the use of anaerobic tanks promotes the phosphorus release reaction of returned sludge under anaerobic conditions, and during periods of low denitrification, such as in winter, the use of raw water and aeration by use of oxygen-free tanks The denitrification reaction of the nitrified liquid returned from the tank 13 to the pre-anoxic tank 11 or the compatible tank 12 is promoted.

 After the treatment in the interchangeable tank 12 as described above, the raw water is supplied to the anoxic tank 6 to be denitrified, and further supplied to the aeration tank 13 for aerobic biological treatment by aeration and stirring. Next, the mixture is supplied from the aeration tank 13 to the settling tank 8, where solid-liquid separation is performed, and the separated liquid is discharged as appropriate. The sludge separated and precipitated is supplied to the concentrator 9 and supplied to the solubilization tank 2. In this case, the aeration tank 13 has a function of removing BOD and nitrification. A portion of the nitrification solution, which is the processing solution in the aeration tank 13,

1, preferably (not shown) returned to anoxic tank 6.

 Further, the sludge solubilized in the solubilization tank 2 is returned to the compatible tank 12, and

2, anaerobic tank 6, aeration tank 13, sedimentation tank 8, concentrator 9, and solubilization tank 2 will be circulated. The sludge separated in the sedimentation tank 8 is supplied not only to the concentrator 9 but also to the former oxygen-free tank 11. Sludge is also returned from the anaerobic tank 4 and the compatible tank 12 to the anoxic tank 11, and the HRT of the solubilizing tank 2 is preferably set to 12 to 72 hours as in the third embodiment, and 24 to 72 hours. HRT of tanks other than solubilization tank 2 is preferably 0.5 to 1.5 hours in anoxic tank 11, and 0.5 to 2 hours in anaerobic tank 4. , 0.5 to 1 hour in the compatible tank 12, 1 to 3 hours in the anoxic tank 6, 3 to 6 hours in the aeration tank 13, 0.5 to 1 hour in the anoxic tank 11 and 0.5 in the anaerobic tank 4. More preferably, it is set to 1 hour, 0.5 to 1 hour in the compatible tank 12, 1 to 2 hours in the anoxic tank 6, and 3.5 to 5 hours in the aeration tank 13.

Examples of microorganisms that produce a solubilizing enzyme for solubilizing sludge include thermophilic bacteria, particularly various Bacillug species disclosed in Embodiment 1 and Geobacillus (Geobacillus). Preference is given to using bacteria of the genus illas).

 Further, the temperature at the time of the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is set so as to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 Although the treatment apparatus of the present embodiment is provided with the concentrator 9, the provision of the concentrator 9 is not an essential condition of the present invention.

 (Embodiment 7)

 In the present embodiment, as shown in FIG. 8, a nitrification tank 10 is provided on the downstream side of the solubilization tank 2, and this is different from the sixth embodiment in this point.

 That is, in the present embodiment, the sludge that has been 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 compatible tank 1

Will be sent back to 2. The sludge separated in the sedimentation tank 8 is supplied to the concentrator 9 as in the sixth embodiment, returned to the oxygen-free tank 11, and is also directly supplied to the nitrification tank 10 in the present embodiment.

 Other configurations and processing procedures are the same as those in the sixth embodiment, and a description thereof will not be repeated.

 Incidentally, the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 18 to 48 hours, and most preferably to 20 to 36 hours, as in the fifth embodiment. It is good.

 Further, as a microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus (Bacillus) 厲 鉀 bacteria disclosed in Embodiment 1 細菌 a bacterium belonging to the genus Geobacillus is used. Is preferred.

Further, the temperature for the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a bacterium belonging to the genus Bacillus is used, 55 to 7 0 ° C The temperature is preferably set within the range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is also set so as to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 (Embodiment 8)

 As shown in FIG. 9, the treatment apparatus of the present embodiment includes a dissolved oxygen reduction tank 16, an anaerobic tank 4, an anoxic tank 6, an aeration tank 13, a sedimentation tank 8, a concentrator 9, and a solubilization tank 2. ing. In this embodiment, in addition to supplying the anaerobic treated water in the anaerobic tank 2 to the anoxic tank 4, the treated water treated to reduce the dissolved oxygen in the dissolved oxygen reducing tank 16 is also anoxic. Supply to tank 6.

 The treated water supplied to the anoxic tank 6 and subjected to denitrification is further supplied to the aeration tank 13 and aerobically treated by aeration and agitation, and further supplied to the settling tank 8 for solid-liquid separation. The separated liquid is discharged as appropriate, and the separated solid sludge is supplied to the concentrator 9 and a part of the sludge is returned to the aeration tank 13.

 In addition, by returning a part of the treatment liquid in the aeration tank 13, that is, a part of the nitrification liquid, to the oxygen-free tank 6 through the dissolved oxygen reduction tank 16, the nitrification liquid is denitrified. The denitrification efficiency can be stabilized by charging the nitrification liquid into the anoxic 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 to be solubilized, and then returned to the dissolved oxygen reduction tank 16.

 The sludge supplied to the anoxic tank 6 is also returned to the anaerobic tank 4, and further returned from the anaerobic tank 4 to the dissolved oxygen reducing tank 16.

The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 24 to 72 hours, and most preferably to 36 to 48 hours, as in the third embodiment. The HRT of the tanks other than the dagger tank 2 is 0.15 to 03 hours in the dissolved oxygen reduction tank 16, 0.5 to 2 hours in the anaerobic tank 4, 1-3 hours in the oxygen-free tank 6, and 3 to 6 hours in the aeration tank 13. Prefer It is more preferable to set the dissolved oxygen reduction tank 16 to 0.17 to 0.25 hours, the anaerobic tank 4 to 1 to 1.5 hours, the anoxic tank 6 to 1 to 2 hours, and the aeration tank 13 to 3.5 to 5 hours.

 As the microorganism that produces a solubilizing enzyme for solubilizing sludge, thermophilic bacteria, in particular, various Bacillus (Eadlks) genus bacteria and Diobacillus (Qeohae illus) genus bacteria disclosed in Embodiment 1 may be used. Is preferred.

 Further, the temperature for the solubilization treatment is preferably in a temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is set to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 (Embodiment 9)

 In the present embodiment, as shown in FIG. 10, a nitrification tank 10 is provided downstream of the solubilization tank 2, which is different from the above-described eighth embodiment in this point.

 That is, in the present embodiment, the sludge that has been subjected to the solubilizing treatment in the solubilization tank 2 is supplied to the nitrification tank 10, and the ammonia in the sludge is converted to nitrous acid or nitric acid in the nitrification tank 10, and the dissolved oxygen It will be returned to the reduction tank 16. Further, a part of the sludge in the settling tank 8 is supplied to the nitrification tank 10 so that the nitrification treatment is maintained.

 Other configurations and processing procedures are the same as those in the eighth embodiment, and a description thereof will not be repeated.

 Incidentally, the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 18 to 48 hours, and most preferably to 20 to 36 hours, as in the fifth embodiment. .

 Examples of microorganisms that produce a soluble enzyme for solubilizing sludge include thermophilic bacteria, particularly various Bacillus (; Bacillus genus bacteria and Geobac ilks bacteria) disclosed in the first embodiment. It is preferred to use

Further, the temperature at the time of the solubilization treatment is in the temperature range of 50 to 90 ° C as in the first embodiment. Desirably, when an aerobic thermophilic bacterium such as a bacterium belonging to the genus Bacillus is used, the temperature is preferably set in the range of 55 to 70 ° C, and more preferably in the range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.

 (Embodiment 10)

 As shown in FIG. 11, the organic wastewater treatment apparatus of the present embodiment includes an anaerobic tank 4, an anoxic tank 6, an aeration tank 13, a sedimentation tank 8, and a solubilization tank 2.

 In the present embodiment, after the anaerobic treatment of the raw water is performed in the anaerobic tank 4 and the phosphorus component in the sludge is released, the phosphorus component is supplied to the anoxic tank 6, and the denitrifying treatment is performed in the anoxic tank 6. The treatment liquid denitrified in the anoxic tank 6 is supplied to the aeration tank 13, where the ammonia contained in the sludge is changed to nitrous acid or nitric acid. That is, nitrification treatment is performed in the aeration tank 13.

 Next, the treatment liquid that has been nitrified in the aeration tank 13 is supplied to the precipitation tank 8. In the sedimentation tank 8, solid-liquid separation is performed, and the separated liquid is discharged and the like. A part of the separated and precipitated solid sludge is supplied to the solubilization tank 2, and the rest is returned. Returned to anaerobic tank 4 as sludge.

 The sludge after solubilization is returned to the anoxic tank 6, denitrification in the anoxic tank 6, treatment in the aeration tank 13, solid-liquid separation in the sedimentation tank 8, and solubilization in the solubilization tank 2. Will be repeated cyclically. A part of the nitrification liquid treated in the aeration tank 13 is returned to the oxygen-free tank 6 or the anaerobic tank 4 and denitrified in the oxygen-free tank 6.

The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 24 to 72 hours, and most preferably to 36 to 48 hours, as in the third embodiment. The HRT for tanks other than 2 should be 0.15 hours for dissolved oxygen reduction tank 16, 0.5 to 2 hours for anaerobic tank 4, 1 to 3 hours for anoxic tank 6, and 3 to 6 hours for aerobic tank 17. Preferably, 0.17 to 0.25 hours in dissolved oxygen reduction tank 16, 1 to 1.5 hours in anaerobic tank 4, anoxic tank 6 More preferably, it is 1 to 2 hours, and the aerobic tank 17 is 3.5 to 5 hours.

 As the microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus (Bacillus ^ genus bacterium ゃ ゃ obacillus (Qeohae ilks) genus bacterium disclosed in Embodiment 1) may be used. Is preferred.

 Further, the temperature at the time of the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is set to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 (Embodiment 11)

 In the present embodiment, as shown in FIG. 12, the sludge solubilized in the solubilization tank 2 is returned to the anaerobic tank 4, which is different from the case of Embodiment 10 in which the sludge is returned to the oxygen-free tank 6. . The anaerobic treatment in the anaerobic tank 4, the denitrification treatment in the oxygen-free tank 6, the nitrification treatment in the aeration tank 13, the solid-liquid separation in the precipitation tank 8, and the solubilization treatment in the solubilization tank 2 are described in the embodiment. It is the same as 10 and its explanation is omitted. Also in this embodiment, a part of the nitrification liquid is returned to the anoxic tank 6 or the anaerobic tank 4.

 II The HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 24 to 72 hours, and most preferably to 36 to 48 hours, as in Embodiment 3. As a microorganism that produces a solubilizing enzyme for solubilizing E. coli, it is preferable to use a thermophilic bacterium, in particular, any of the various bacterium belonging to the genus Bacillus and the genus Oeohae illus disclosed in the first embodiment.

Further, the temperature at the time of the fusi-dani treatment is preferably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, It is preferable to set the temperature in the range of 55 to 70 ° C, more preferably in the range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is in the range of pH 6 to 9, preferably 7 to 7, as in the first embodiment. Set to be in the range of 8.

 (Embodiment 12)

 In the present embodiment, as shown in FIG. 13, a nitrification tank 10 is provided downstream of the solubilization tank 2. In the present embodiment, the sludge treated 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 returned to the oxygen-free tank 6. become. Further, sludge is supplied from the settling tank 8 to the nitrification tank 10.

 The anaerobic treatment in the anaerobic tank 4, the denitrification treatment in the oxygen-free tank 6, the nitrification treatment in the aeration tank 13, the solid-liquid separation in the precipitation tank 8, and the solubilization treatment in the solubilization tank 2 are described in the embodiment. It is the same as 11 and its explanation is omitted.

 However, the HRT of the solubilization tank 2 is preferably set to 12 to 72 hours, more preferably to 18 to 48 hours, and most preferably to 20 to 36 hours as in the fifth embodiment. Is also preferred.

 In addition, as a microorganism that produces a solubilizing enzyme for solubilizing sludge, a thermophilic bacterium, in particular, various Bacillus (Bacillus) genus bacteria disclosed in Embodiment 1 and ゃ diobacillus (Qsohae ilks) bacterium are used. Is preferred.

 Further, the temperature for the solubilization treatment is preferably in a temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is also in the range of pH 6 to 9 as in Embodiment 1, preferably? Set to be in the range of ~ 8.

 (Embodiment 13)

 In this embodiment, as in the twelfth embodiment, the nitrification tank 10 is provided downstream of the solubilization tank 2, and the sludge treated in the nitrification tank 10 is subjected to anaerobic sodium carbonate as shown in FIG. This is different from the case of the twelfth embodiment in which it is returned to the oxygen-free tank 6.

The anaerobic treatment in the anaerobic tank 2, the denitrification treatment in the anoxic tank 6, the nitrification treatment in the aeration tank 13, the solid-liquid separation in the precipitation tank 8, and the solubilization treatment in the solubilization tank 2 are described in the embodiment. Same as 10 The description is omitted.

 The HRT of the fusible tank 2 is preferably set to 12 to 72 hours, more preferably to 18 to 48 hours, and most preferably to 20 to 36 hours, as in the fifth embodiment. Better.

 Also in this embodiment, similarly to Embodiment 12, the supply of sludge from the settling tank 8 to the nitrification tank 10 is required.

 In addition, as a microorganism that produces a solubilizing enzyme for solubilizing sludge, thermophilic bacteria, in particular, various Bacillus genus bacteria disclosed in Embodiment 1 ゃ Diobacillus (Qeobae illas) genus bacteria may be used. Is preferred.

 Further, the temperature at the time of the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is also set to be in the range of pH 6 to 9, preferably 7 to 8, as in the first embodiment.

 (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 treatment of the organic wastewater is performed batchwise as in the first embodiment.

 In this embodiment, as shown in FIG. 16, the process of anaerobic treatment by agitation and the process of aerobic treatment by aeration are repeated three times, and thereafter, the steps of precipitation, solid-liquid separation, and solubilization by stopping the aeration are performed. Is circulated. The process of repetition of anaerobic and aerobic treatment, precipitation, and solid-liquid separation are performed in the reaction tank 1, and the solubilization process is performed in the solubilization tank 2.

The batch treatment of a series of wastewater treatments, from the inflow of raw water to the discharge of treated water, can be performed several times a day (for example, 2 to 4 times), and the treatment time of each process can be adjusted. About once a day or about twice a day depending on the properties and quantity of The processing time of each step may be adjusted so as to perform the processing.

 The duration of the wastewater treatment process is, for example, inflow 60 minutes, anaerobic 60 minutes, aerobic 70 minutes, anaerobic 30 minutes, aerobic 80 minutes, anaerobic 20 minutes, aerobic 10 minutes, sedimentation 40 minutes, and discharge 40 minutes. I have.

 In the present embodiment, nitrification is performed in the aerobic treatment step, and denitrification treatment is performed in the anaerobic treatment step.

 The solubilized liquid 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 treatment step, and is set to 3 to 30 minutes before the aeration stop, preferably 1 to 30 minutes. In the present 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 treated in the solubilization tank 2 in the storage tank 3. This is preferable because the timing and amount of returning the solubilized solution 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.

 As a microorganism that produces a solubilizing enzyme for solubilizing sludge, it is preferable to use a thermophilic bacterium, in particular, a bacterium belonging to the genus Bacillus (Mmds) belonging to the genus Bacillvs described in Embodiment 1. preferable.

 Further, the temperature at the time of the solubilization treatment is desirably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as a Bacillus bacterium is used, 55 The temperature is preferably set to a temperature range of 70 to 70 ° C, and more preferably a temperature range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is also in the range of pH 6 to 9 as in Embodiment 1, preferably? Set to be in the range of ~ 8.

 (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 subsequent stage of the reaction tank 1 and a solubilization tank 2 at the subsequent stage. In the present embodiment, the sludge after the nitrification and denitrification treatment is temporarily stored in the storage tank 3, and the required amount to be solubilized Sludge is supplied to the solubilization tank 2.

 By supplying only the required amount of sludge to be solubilized to the solubilization tank 2 in this way, it is possible to adjust the amount of soluble liquor to be returned to the aerobic treatment process in advance. It becomes. The anaerobic process and the aerobic process are repeated, followed by precipitation and solid-liquid separation, as in 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.

 As a microorganism that produces a solubilizing enzyme for solubilizing sludge, it is preferable to use thermophilic bacteria, particularly various Bacillus (Bacillus ^ genus bacteria and Geobacillus genus bacteria disclosed in Embodiment 1). .

 Further, the temperature at the time of the fusi-dani treatment is preferably in the temperature range of 50 to 90 ° C. as in Embodiment 1, and when an aerobic thermophilic bacterium such as Bacillus bacterium is used, It is preferable to set the temperature in the range of 55 to 70 ° C, more preferably in the range of 60 to 65 ° C. Further, the pH at the time of the solubilization treatment is set to be in the range of 6 to 9, preferably 7 to 8, as in the first embodiment.

 (Embodiment 16)

 This embodiment is an embodiment provided with a means for removing phosphorus when sludge generated by biological treatment such as nitrification or denitrification contains phosphorus.

 In the present embodiment, a coagulant such as polychlorinated aluminum is added to remove phosphorus by coagulation and sedimentation on the downstream side of the precipitation tank 8 as in each of the above embodiments, or coagulation filtration is performed by providing a filter material. Removes phosphorus.

In the above-mentioned embodiments, in the embodiment having the anaerobic treatment step and the aerobic treatment step (aeration treatment step), if the treated water or the sludge contains phosphorus, the phosphorus is contained in the sludge in the anaerobic treatment step. Released from microorganisms and taken up by microorganisms in the aerobic treatment process. However, even if phosphorus is released and taken up in this way, if the sludge solubilization treatment is incorporated, the treatment liquid containing phosphorus may be discharged out of the system. The effect of releasing and taking in phosphorus cannot be achieved due to both of the above steps.

 Therefore, by providing the phosphorus removing means as described above, the phosphorus contained in the treated water or sludge can be positively removed. This applies to both continuous and batch processing.

 (Embodiment 17)

 In the present embodiment, instead of the means using the flocculant or the like as the phosphorus removing means, a phosphorus release tank provided with a phosphorus separating means is provided at the subsequent stage of the sedimentation tank 8, and the sludge separated in the sedimentation tank 8 is removed. In the phosphorus release tank, the phosphorus is released by exposing it to a state in which phosphorus is released from sludge, for example, in an anaerobic state or a heated state, and the released phosphorus is separated into a phosphorus release sludge and a phosphorus eluate to form a phosphorus release liquid It is configured so that it can be removed by adding a coagulant or the like. And the phosphorus release sludge is subjected to solubilization.

 Therefore, also in the present embodiment, various tanks as in the above-described embodiments can be provided on the upstream side of the precipitation tank 8. This applies to both continuous and batch processing.

 (Embodiment 18)

 In the present embodiment, iron plate, iron particles, steel wool, etc. are charged into the reaction tank 1, aeration tank 13, nitrification tank 10, solubilization tank 2, oxygen-free tank 6, etc. Is an embodiment in which phosphorus is removed by adhering to iron.

 In the present embodiment, the existing reaction tank 1 is installed in the processing apparatus without using a coagulant 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 charging the iron material into the aeration tank 13, the solubilization tank 2, the oxygen-free tank 6, etc., the phosphorus component can be attached to the iron material to easily remove the phosphorus. (Other embodiments)

In the above-described Embodiments 3, 4, and 5, etc., the acid-fermented liquid obtained by gas-decomposing the remaining rice discharged from the food factory and fermenting was used as the liquid to be treated, but the type of the substance to be treated is limited to this It doesn't matter what the type. Also, the provision of the fermentation liquid storage tank 3 is not an essential condition for the present invention as in Embodiments 3, 4, and 5, for example, as shown in FIG. 18, the fermentation liquid storage tank 3 is not provided, and the anaerobic tank is not provided. 4. It is also possible to use a treatment apparatus equipped with a primary aeration tank 5, an oxygen-free tank 6, a secondary aeration tank 7, a precipitation tank 8, and a solubilization tank 2. For example, when treating only sewage from a sewage treatment plant, the treatment apparatus shown in FIG. 18 can be suitably used.

 Furthermore, exhaust gas may be discharged from the fusible tank 2. By introducing such exhaust gas into the nitrification tank and the aeration tank of the above embodiment, it is possible to remove the odor of the exhaust gas, By introducing high-temperature exhaust gas into the nitrification tank and the aeration tank, the temperature of each tank can be higher than that of normal air aeration, thereby increasing the activity of microorganisms and, as a result, increasing the processing efficiency. It is preferred.

 Furthermore, the type of organic wastewater to be treated does not matter.

Claims

The scope of the claims

1. A method for biologically treating organic wastewater, which comprises nitrifying and denitrifying organic wastewater and then solubilizing sludge generated by nitrification and denitrification. Wastewater treatment method.

 2. The method for treating organic wastewater according to claim 1, wherein the nitrification and denitrification of the organic wastewater are performed batchwise in the reaction tank 1.

 3. 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.

4. The method for treating organic wastewater according to claim 2 or 3, wherein the solubilized solution is returned to the reaction tank 1 from 3 hours to 30 minutes before stopping the aeration.

 5. The method for treating organic wastewater according to claim 2, wherein the solubilized solution is returned to the reaction tank 1 from 1 hour to 30 minutes before stopping the aeration.

 6. 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.

7. The nitrification and denitrification treatment of organic wastewater is performed by a denitrification process in an anoxic tank, an anaerobic treatment step, a treatment step in an exchange tank, a denitrification step in an anoxic tank, and an aeration step. The organic wastewater treatment method described in 1.

 8. The method for treating organic wastewater according to claim 6, wherein nitrification is performed after the solubilization treatment. 9. A request for nitrification and denitrification of organic wastewater by an anaerobic treatment step, a denitrification step in an anoxic tank, and an aeration step, and to reduce the dissolved oxygen in the treatment liquid after the solubilization treatment. The method for treating organic wastewater according to 1.

 10. 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 anoxic tank, and an aeration step.

11. The organic matter according to any one of claims 1 to 10, wherein the sludge is concentrated before the solubilization treatment. Wastewater treatment method.

 12. The method for treating organic wastewater according to any one of claims 1 to 11, wherein the solubilization of the sludge is performed by an aerobic thermophilic bacterium.

 13. The method for treating organic wastewater according to claim 12, wherein the aerobic thermophilic bacterium is a microorganism of the genus Bacillus.

 14. The method for treating organic wastewater according to any one of claims 1 to 13, further comprising a step of removing phosphorus in sludge generated by nitrification and denitrification.

 15. 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 characterized.

 16. 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.

 17. The method according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is means for nitrifying and denitrifying by the anaerobic tank 4, the primary aeration tank 5, the oxygen-free tank 6, and the secondary aeration tank 7. Organic wastewater treatment equipment.

 18. The method according to claim 15, wherein the means for nitrifying and denitrifying the organic wastewater is a means for nitrifying and denitrifying by the former oxygen-free tank 11, the anaerobic tank 4, the compatible tank 12, the oxygen-free tank 6, and the aeration tank 13. Organic wastewater treatment equipment.

 1 9. Means for nitrifying and denitrifying organic wastewater are means for nitrifying and denitrifying by anaerobic tank 4, anoxic tank 6, and aeration tank 13, reducing the dissolved oxygen in the treated liquid after solubilization. The organic wastewater treatment apparatus according to claim 15, further comprising a dissolved oxygen reduction tank (16).

 20. 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 by the anaerobic tank 4, the anoxic tank 6, and the aeration tank 13.

 21. 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.