JP2006239625A - Method and equipment for treating organic waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a method and equipment for treating organic waste which achieve reduction in power for solubilization, and which efficiently treat even organic waste of high concentration. <P>SOLUTION: The equipment for treating organic waste is provided with a methane fermentation tank 12 methane-fermenting organic waste; and a biological denitrification equipment 13 biologically treating digested sludge 21 discharged from the methane fermentation tank, the equipment for treating organic waste is further provided with; a solubilization tank 30 solubilizing biologically-treated liquid 22 discharged from the biological denitrification equipment 13 to obtain solubilized sludge; and a solubilized sludge return line returning at least part 23 of the solubilized sludge to the methane fermentation tank 12, or to the upstream side of the tank 12. Preferably the solubilization tank 30 is composed of a colloidalization means colloidalizing mainly the biologically-treated liquid 22, and a liquefying means liquefying mainly the colloidalized treated liquid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technology for methane fermentation of organic waste, and in particular, methane fermentation efficiently even for high-concentration organic waste containing a large amount of organic solids such as garbage, food processing residues, and livestock manure. The present invention relates to a processing method and processing equipment for organic waste.

2. Description of the Related Art Conventionally, a methane fermentation process that has a low environmental load and can recover energy and resources has been widely used as a method for treating organic waste.
A typical methane fermentation process is shown in FIG. First, after crushing large-sized organic waste and removing contaminants, the pH, temperature, amount of water, concentration, etc. of the waste are adjusted to conditions suitable for methane fermentation in the adjustment tank 51, and the adjusted waste The product is subjected to methane fermentation in the methane fermentation tank 52. In the methane fermentation tank 52, organic substances in the waste are decomposed by the action of anaerobic microorganisms, and the generated biogas is recovered. The recovered biogas is desulfurized and gas purified and then used for power generation. On the other hand, the digested sludge generated in the methane fermentation tank 52 is fed to a biological denitrification treatment facility 53, where nitrification and denitrification treatment are performed to remove nitrogen, BOD and the like in the sludge. A part of the processing liquid is returned to the adjustment tank 51 as dilution water, and the other processing liquid is solid-liquid separated by the solid-liquid separation device 54, and the separated liquid is discharged after being purified by the advanced processing device 55. Is done. The sludge separated by the solid-liquid separator 54 was treated by the sludge treatment facility 56.

In such methane fermentation, volume reduction of sludge is required, but digested sludge produced by methane fermentation is difficult to filter and solid-liquid separation by sedimentation separation is difficult, and sludge generation after solid-liquid separation is large Therefore, there has been a problem that the sludge treatment facility is enlarged and the treatment cost is increased.
Thus, a method for reducing the amount of sludge generated by solubilizing digested sludge after methane fermentation has been proposed and put to practical use. In the solubilization treatment, the organic matter in the digested sludge is reduced in molecular weight by methods such as ozone oxidation, heating, and alkali addition, and the organic matter decomposition rate in the subsequent biological treatment is improved to reduce the sludge volume.

In Patent Document 1 (Japanese Patent Laid-Open No. 9-122682), sewage is first solid-liquid separated in a sedimentation basin, and the separated organic SS is biologically treated by an activated sludge method, and the activated sludge from the biological treatment is solidified. A sewage treatment method is disclosed in which a biological treatment liquid is obtained by liquid separation. In this treatment method, raw sludge separated in a first sedimentation basin and biological sludge extracted from the biological treatment are subjected to methane fermentation, and then ozone It is oxidized and returned to the biological treatment.
According to this method, the digested sludge after methane fermentation is ozone-oxidized to solubilize the organic matter in the sludge, and then biological treatment is performed. Therefore, it is possible to reduce the volume of the sludge and improve the treatment liquid properties. is there.

Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2003-88895), organic waste is methane-fermented, the digested sludge generated by this methane fermentation is solubilized by ozone oxidation, and the solubilized sludge is solid-liquid separated. And the method of returning a part of said solubilized sludge to a methane fermenter while disposing the isolate | separated separated liquid into wastewater is disclosed.
Thus, it becomes possible to improve the decomposition efficiency of methane fermentation by solubilizing the hardly decomposable substance contained in the digested sludge after methane fermentation by ozone oxidation and performing methane fermentation again.

JP-A-9-122682 JP 2003-88895 A

However, as described in Patent Documents 1 and 2, when the digested sludge after methane fermentation is subjected to ozone oxidation, the digested sludge has a high anaerobic degree and contains a large amount of undegraded organic matter. There was a problem that it became high, solubilization power was large, and cost increased.
In addition, sludge volume reduction can be expected by performing solubilization treatment after methane fermentation, but in the case of high-concentration organic waste that contains a lot of organic solids such as garbage, food processing residues, livestock manure, Even if the solubilization treatment is performed, it is difficult to reduce the solid concentration, and the sludge volume reduction effect is small. Therefore, there has been a problem that the sludge treatment facility is enlarged and the treatment cost is increased.
In view of the above-described problems of the prior art, the present invention can reduce solubilization power, and can treat organic waste efficiently even if it is a high concentration organic waste. The purpose is to provide equipment.

Therefore, in order to solve this problem, the present invention provides:
In a method for treating organic waste, comprising: a methane fermentation process for methane fermentation of organic waste; and a biological denitrification process for biologically denitrifying digested sludge produced by the methane fermentation. ,
A solubilization process for obtaining a solubilized sludge by solubilizing a biological treatment liquid from the biological denitrification process is provided, and at least a part of the solubilized sludge is obtained from the methane fermentation process or the methane fermentation process. It is returned to the upstream side.

According to the present invention, the amount of sludge generated in the entire equipment is reduced in order to solubilize the treatment solution that has been aerobically treated in biological denitrification treatment and to make it easily decomposed in methane fermentation. In addition, the amount of methane gas generated can be increased.
In methane fermentation, nitrogen in the protein is converted to ammonia nitrogen with the decomposition of organic matter. Since ammonia nitrogen is an inhibitory component of methane fermentation, it is necessary to keep the concentration in the methane fermentation tank at 3000 to 5000 ppm or less. Since the decomposed treatment liquid is solubilized and returned to the methane fermentation tank, the ammonia nitrogen concentration in the methane fermentation tank can be diluted, and efficient methane fermentation becomes possible.
In addition, digested sludge with high anaerobicity produced by methane fermentation is once treated aerobically by biological denitrification treatment, so that a treatment solution with properties suitable for solubilization is introduced into the solubilization treatment. Since the undegraded colloidal component remaining in the digested sludge is reduced by the biological denitrification treatment, the power in the solubilization equipment can be reduced.

Further, the solubilization step is characterized by comprising a colloidalization step in which the biological treatment liquid is mainly colloided and a liquefaction step in which the colloidalized treatment liquid is mainly liquefied. In the solubilization step, the biological treatment liquid is colloided by ozone oxidation in the colloidalization step, and cavitation is generated in the colloidal treatment liquid in the liquefaction step to be liquefied.
According to the present invention, since the solubilization treatment includes a colloidalization step and a liquefaction step, high-efficiency treatment is possible even with a high concentration of organic waste. The highly anaerobic digested sludge produced by the methane fermentation has been converted to aerobic by biological denitrification treatment, so that it is in a state suitable for ozone oxidation, is capable of ozone oxidation with high efficiency, and consumes ozone. The amount can be reduced.

In addition, a method for treating organic waste comprising a solid-liquid separation step for obtaining a separated liquid and separated sludge by solid-liquid separation of at least a part of the solubilized sludge,
A second biological denitrogenation that biologically denitrifies the solubilized sludge or the solid-liquid separation solution between the solubilization step and the solid-liquid separation step or after the solid-liquid separation step. A processing step is provided.
In this way, by providing the second biological denitrification treatment step, ammonia nitrogen generated by solubilization can be surely removed, and finally generated ammonia nitrogen is discharged out of the system. There is no fear. In addition, digested sludge after methane fermentation usually has a low BOD / N ratio and may require a nutrient source such as methanol in the biological denitrification process. Then, since the solubilization treatment is performed on the upstream side, the BOD / N ratio is improved, and the amount of the nutrient source added can be reduced or eliminated.

In addition, a solid-liquid separation step for obtaining a separated liquid and separated sludge by solid-liquid separation of the biological treatment liquid is provided after the biological denitrification treatment step, and the separated sludge is introduced into the solubilization step. And
According to the present invention, since the sludge concentrated by solid-liquid separation is solubilized, the amount of liquid to be solubilized can be reduced, and solubilization power can be reduced.

In addition, a solid-liquid separation step for obtaining a separated liquid and separated sludge by solid-liquid separation of organic waste is provided before the methane fermentation step, and the separated sludge is introduced into the methane fermentation step, It introduce | transduces into the said biological denitrification process process, It is characterized by the above-mentioned.
Furthermore, the present invention is characterized in that a liquid waste having a small solid content is introduced into the biological denitrification step, and the liquid waste is treated together with the digested sludge.
According to these inventions, by providing the solid-liquid separation step before the methane fermentation step, the load of water flowing into the methane fermentation can be reduced, so that the apparatus can be made compact. In addition, by introducing liquid waste or separation liquid into biological denitrification treatment, the BOD components contained in these can be used as nutrient sources during denitrification, and external to nutrient sources such as methanol The amount added can be reduced or eliminated.

An organic waste comprising: a methane fermentation apparatus for methane fermentation of organic waste; and a biological denitrification apparatus for biologically denitrifying digested sludge discharged from the methane fermentation apparatus. In processing equipment,
There is provided a solubilization device for obtaining a solubilized sludge by solubilizing a biological treatment liquid discharged from the biological denitrification treatment device, and at least a part of the solubilized sludge is used as the methane fermentation device or the methane A solubilized sludge return line is provided for returning to the upstream side of the fermenter.
At this time, the solubilization apparatus is characterized by comprising a colloiding means for mainly colloiding the biological treatment liquid and a liquefaction means for mainly liquefying the colloidal treatment liquid. In the solubilization apparatus, the biological treatment liquid is colloided by ozone oxidation by the colloiding means, and cavitation is generated in the colloidal treatment liquid by the liquefaction means so as to be liquefied. To do.

Moreover, it is an organic waste treatment facility equipped with a solid-liquid separation device that separates at least a part of the solubilized sludge to obtain a separated liquid and separated sludge,
A second biological denitrification apparatus for biologically denitrifying the solubilized sludge or the separated liquid between the solubilizer and the solid-liquid separator or at the subsequent stage of the solid-liquid separator. Is provided.
In addition, a solid-liquid separation device that separates the biological treatment liquid into solid and liquid to obtain a separation liquid and separated sludge is provided at a subsequent stage of the biological denitrification treatment apparatus, and the separated sludge is introduced into the solubilization apparatus. It is characterized by.
Furthermore, a solid-liquid separation device is provided in the preceding stage of the methane fermentation apparatus to obtain a separated liquid and separated sludge by solid-liquid separation of organic waste, the separated sludge is introduced into the methane fermentation apparatus, and the separated liquid is It introduce | transduces into the said biological denitrification processing apparatus, It is characterized by the above-mentioned.
Furthermore, the biological denitrification apparatus is provided with a liquid waste input line having a low solid content, and the liquid waste is treated together with the digested sludge.

As described above, according to the present invention, since the solubilization is performed after the biological denitrification treatment and the solubilized sludge is returned to the methane fermentation or its upstream side, it can be efficiently used with less solubilization power. Sludge volume reduction can be realized.
This is because digested sludge produced by methane fermentation is treated with aerobic treatment by biological denitrification once, so that a treatment solution with properties suitable for solubilization is introduced into the solubilization treatment. This is because the undegraded colloidal component remaining in the digested sludge is reduced by the biological denitrification treatment, and the power in the solubilization equipment can be reduced.
Further, since the solubilization treatment includes a colloidalization step and a liquefaction step, high-efficiency treatment is possible even with a high concentration of organic waste.
Moreover, by providing the second biological denitrification treatment step, ammonia nitrogen generated by solubilization can be surely removed, and finally generated ammonia nitrogen may be discharged out of the system. This disappears.
Furthermore, the amount of liquid to be solubilized can be reduced and the solubilization power can be reduced by solid-liquid separation of biological treatment liquid from biological denitrification treatment and solubilization of sludge concentrated by solid-liquid separation. can do.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
Examples of the treatment target of this embodiment include organic waste such as food waste, food processing residue, livestock waste, and sludge generated by water treatment such as sewage treatment. Suitable for the treatment of high concentration organic waste such as residues.
FIG. 1 is a flowchart showing an outline of a treatment system according to Embodiment 1 of the present invention, FIG. 2 is a schematic configuration diagram showing an example of the solubilization equipment of this embodiment, and FIG. 3 is a specific example of the solubilization equipment of this embodiment. FIG. 4 is a schematic sectional view showing an ozone generator used in the solubilization equipment of FIG. 3, FIG. 5 is a schematic construction diagram showing a cavitation device used in the solubilization equipment of FIG. 6 is a flowchart showing an outline of the processing system according to the second embodiment of the present invention, FIG. 7 is a schematic configuration diagram showing an example of the solubilization equipment of FIG. 6, and FIG. 8 is a diagram of the processing system according to the third embodiment of the present invention. It is a flowchart which shows an outline.

  As shown in FIG. 1, the organic waste processing apparatus according to the first embodiment includes an adjustment tank 11 that performs an acid generation process of the organic waste 20 from the upstream side to the downstream side of the line, and the adjustment tank 11. The organic waste 20 is supplied, the methane fermentation tank 12 that performs the methane production process of the organic waste 20, and the digested sludge 21 generated in the methane fermentation tank 12 are supplied, and the action of aerobic / anaerobic microorganisms The biological denitrification treatment facility 13 in which nitrification and denitrification is performed by the above and the biological treatment solution 22 that has been subjected to biological denitrification treatment are introduced, and the solubilization facility 30 that colloidizes and liquefies the biological treatment solution And at least a part of the solubilized sludge, and the solid-liquid separation device 14 that performs solid-liquid separation into the separation liquid 25 and the separation sludge 26; the advanced processing device 15 that performs high-level treatment of the separation liquid 25; and the separation The sludge that treats sludge 26 It is provided with a processing facility 16, a.

The processing apparatus in the present embodiment is provided with preprocessing equipment such as a crushing means for crushing large-diameter organic waste and a sorting means for removing impurities and the like in the previous stage of the adjustment tank 11.
A methane fermentation apparatus composed of an adjustment tank 11 and a methane fermentation tank 12 is provided at the subsequent stage of the pretreatment facility.
The adjustment tank 11 has means for adjusting the pH, temperature, amount of water, concentration, and the like of the organic waste 20 to conditions suitable for methane fermentation, a stirring means, and the like, and mainly hydrolyzes organic matter in the waste. An acid production stage is carried out to acid ferment.
In the methane fermentation tank 12, anaerobic microorganisms are propagated in the tank, and conditions such as temperature and pH are maintained in an environment where the anaerobic microorganisms can prominently propagate. A methane production step is performed, and biogas, digestive fluid as a supernatant, and digested sludge 21 are generated. In this embodiment, the methane fermentation tank 12 may be either a medium temperature methane fermentation treatment tank or a high temperature fermentation treatment tank. In the case of the medium temperature methane fermentation treatment tank, the temperature condition in the tank is about 30 to 40 ° C. In the case of the high-temperature fermentation treatment tank, the temperature condition in the tank is about 50 to 60 ° C.

The biological denitrification equipment 13 has a configuration in which a plurality of anaerobic tanks, aerobic tanks, and sedimentation tanks are combined, and mainly the BOD, nitrogen compounds, etc. in the digested sludge by the action of nitrifying bacteria and denitrifying bacteria. It is a device for decomposing and removing.
The solid-liquid separation device 14 is a device for separating the solubilized sludge into the separation liquid 25 and the separation sludge 26, and a gravity sedimentation method, a centrifugal separation method, a membrane separation method, a coagulation separation method, a flotation separation method, or the like is used. .
Examples of the advanced processing device 15 include a coagulation separation device, an activated carbon adsorption tower, and the like. The processing solution after the solid-liquid separation may be installed as necessary when the processing liquid does not reach the discharge level.
The sludge treatment facility 16 is a facility for performing dehydration, drying, incineration, composting and the like of the separated sludge 26.

The solubilizing equipment 30 includes ozone oxidizing means, ultrasonic means, heating means including hydrothermal, lytic enzyme supplying means, cavitation generating means, oxidizing agent adding means, electrolysis means, alkaline agent adding means, mechanical shearing / friction. As shown in FIG. 2, the colloid of the biological treatment liquid 22 has at least one of the means or a combination of two or more of these means, and in one or more tanks having the solubilizing means. The liquefaction step 30A and the liquefaction step 30B are performed.
In the colloidalization step 30A, the organic matter in the biological treatment liquid is reduced in molecular weight by a solubilizing means and colloidalized mainly. The liquefaction step 30B is performed after the colloidalization step 30A, and the colloidalized low molecular weight organic substance is liquefied mainly by a solubilizing means.

Among the solubilizing means, the ozone oxidizing means brings ozone generated by an ozone generator or the like into a gas-liquid contact with the biological treatment liquid 22, and reduces the high molecular organic matter in the treatment liquid by the strong oxidizing power of ozone. Solubilize by molecularization. Further, the ultrasonic means is provided with an ultrasonic generator to generate ultrasonic waves in the biological treatment liquid, and crush and solubilize the cell walls of microorganisms by ultrasonic vibration. The heating means is intended to lower the molecular weight of the treatment liquid by hydrothermal reaction by applying heat to the organic matter. The lytic enzyme supply means performs solubilization by decomposing the cell wall of the microorganism with bacteria having strong lytic activity. The cavitation generating means is means for generating fine bubbles in the biological treatment liquid, and examples thereof include those that generate cavitation by releasing the pressure after pressurization. This configuration will be described later. As the oxidizing agent adding means, known oxidizing agents such as hydrogen peroxide, calcium peroxide, ammonium persulfate and hypochlorous acid are used, but hydrogen peroxide is most preferable from the viewpoint of cost and by-products, By adding the oxidizing agent, the organic substance is oxidized and decomposed to solubilize. The electrolysis means kills microorganisms by flowing an electric current between electrodes immersed in the treatment tank, and destroys a part of the cell wall and cell membrane to perform solubilization. As the alkali agent adding means, a known alkali agent such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, calcium oxide, sodium oxide or the like can be used. As the mechanical shearing / friction means, for example, a device such as a bead mill or a disk mill can be used, and a shearing force / friction force is applied to the biological treatment liquid to mechanically crush and reduce the molecular weight.
In addition to these solubilizing means, it is also preferable to add an aeration means as an auxiliary.

A preferred embodiment of the solubilization equipment 30 is shown in FIG. As shown in FIG. 3, the solubilization facility 30 includes a storage tank 30C in which the biological treatment liquid 22 is stored, and the biological treatment liquid 22 is supplied from the storage tank 30C, and the biological treatment liquid 22 is mainly formed by ozone. The ozone oxidizer 30A for colloidalization, and the cavitation device 30B for generating cavitation in the processing liquid supplied from the ozone oxidizer 30A and liquefying it.
The ozone oxidizer 30A ejects ozone generated by the ozone generator 130 from an air diffuser installed in a reaction tank in which the biological treatment liquid 22 is stored, and makes contact with the biological treatment liquid while stirring the inside of the tank. It is the composition to do.

An example of the ozone generator 130 is shown in FIG. 4A is a flat plate type, and FIG. 4B is a multi-tube type. In the ozone generator 130, a glass plate 131, which is a solid insulator, is disposed on one surface of an electrode, an alternating voltage is applied between the electrodes to form a discharge space 132 that continues in the gap, and generates ozone. Thus, ozone having a concentration of 3 to 4% when air is used as a raw material and 6 to 8% when oxygen is used as a raw material can be obtained.
In the ozone oxidizer 30A, the organic matter in the treatment liquid is reduced in molecular weight by the strong oxidizing power of ozone, and becomes mainly colloidal. Of course, at this time, the biological treatment liquid partially includes a liquid portion and a solid portion.

FIG. 5 shows a schematic configuration of the cavitation device 30B. The cavitation device 30B includes a pressurizing pump 136 and a pipe 137 whose internal flow path is narrowed in an orifice shape, and the biological treatment liquid 22 introduced into the pipe 137 is in a constricted portion of the pipe 137. The pressurizing pump 136 is pressurized to several hundred kPa to several MPa, preferably 200 to 500 kPa, and then cavitation occurs due to vortex flow in the flow path expanding portion. At this time, various conditions such as the narrowed portion and the diameter of the enlarged portion of the pipe 137 are determined by the processing target processing liquid.
According to the cavitation apparatus 30B, a local high temperature and high pressure field is formed in the vicinity of the cavitation, and OH radicals are generated. Since the OH radical has a strong oxidizing power, the solid and colloidal substances in the biological treatment liquid are reduced in molecular weight, liquefied and solubilized by the OH radical.
In addition, in a present Example, it is not limited to the structure of the above-mentioned ozone generator 130 and the cavitation apparatus 30B, It is applicable if it is an apparatus which can achieve the same objective.

About the processing equipment which has the above composition, the operation is explained with a processing method.
First, the organic waste 20 that has undergone pretreatment such as crushing / sorting is supplied to the adjustment tank 11, and the pH, temperature, water amount, concentration, etc. of the organic waste are methane fermentation in the adjustment tank 11. The acid generation step is performed in which the organic matter in the waste is mainly hydrolyzed and acid-fermented. The adjusted organic waste 20 is introduced into the methane fermentation tank 12 and methane-fermented with anaerobic microorganisms in the methane fermentation tank 12.
Digested sludge 21 generated in the methane fermentation tank 12 is fed to a biological denitrification treatment facility 13, and after nitrification / denitrification, the biological treatment liquid 22 is fed to a solubilization facility 30. In the solubilization equipment 30, the biological treatment liquid 22 is colloided, and then the colloidal treatment liquid is liquefied to obtain a solubilized sludge.

At least a part of the solubilized sludge is introduced into the solid-liquid separation device 14, and the solid-liquid separation device 14 performs solid-liquid separation into the separation liquid 25 and the separation sludge 26. After the purification, the treated water 27 is discharged. The sludge 26 is subjected to processing such as incineration and composting in the sludge treatment facility 16.
On the other hand, the other part 23 of the solubilized sludge is returned to the adjustment tank 11 or the methane fermentation tank 12. At this time, it goes without saying that it may be returned onto a waste feed pipe located upstream of the methane fermentation tank 12.
Further, the other part 24 of the solubilized sludge may be returned to the biological denitrification facility 13 or just before that.

According to the present embodiment, since solids (SS component) are reduced by the solubilization treatment, the treatment liquid aerobically treated in the biological denitrification treatment can be solubilized and decomposed in the methane fermentation. Because of the properties, the amount of sludge generated in the entire facility can be reduced, and the amount of methane gas generated can be increased.
In addition, since the solubilization treatment includes a colloidalization step and a liquefaction step, high-efficiency treatment is possible even with high-concentration organic waste.
Further, in the methane fermentation tank 12, nitrogen in the protein is converted to ammonia nitrogen with the decomposition of the organic matter. Since ammonia nitrogen is an inhibitory component of methane fermentation, it is necessary to keep the concentration in the methane fermentation tank at 3000 to 5000 ppm or less. Since the treatment liquid after the decomposition of the functional nitrogen to some extent is solubilized and returned to the methane fermentation tank 12, the ammonia nitrogen concentration in the methane fermentation tank 12 can be diluted.
Further, since the highly anaerobic digested sludge 21 discharged from the methane fermentation tank 12 is aerobically treated by the biological denitrification treatment equipment 13, a treatment liquid 22 having properties suitable for solubilization is obtained. Since the undecomposed colloidal component remaining in the digested sludge 21 is reduced by the biological denitrification treatment, the power in the solubilization facility 30 can be reduced.
Furthermore, since at least a part 24 of the solubilized sludge is returned to the biological denitrification facility 13, the BOD generated by solubilization can be used as a nutrient source necessary for denitrification, such as methanol. Can reduce external addition of nutrient sources.

Further, as another configuration of the present embodiment, between the solubilization equipment 30 and the solid-liquid separation device 14 (* 1) or between the solid-liquid separation device 14 and the advanced processing device 15 (* 2), A second biological denitrification facility may be provided.
When it is provided between the solubilization facility 30 and the solid-liquid separation device 14 (* 1), the second biological denitrification treatment device is a device in which a nitrification layer, a denitrification tank and a precipitation tank are combined. It is preferable that
When provided between the solid-liquid separator 14 and the advanced processor 15 (* 2), a biological fixed bed is suitable as the second biological denitrification facility.

In the solubilization facility 30, soluble nitrogen such as ammoniacal nitrogen is generated along with the solubilization of the treatment liquid. By providing the second biological denitrification treatment facility, it is ensured that it is ammoniac. Nitrogen treatment can be performed, and there is no possibility that ammonia nitrogen finally generated is discharged out of the system.
In addition, digested sludge after methane fermentation usually has a low BOD / N ratio, and when nitrification denitrification is performed in the latter stage, a nutrient source such as methanol is required. In the second nitrification denitrification treatment, Since the solubilization treatment is performed on the upstream side, the BOD / N ratio is improved, and the amount of nutrients added can be reduced or eliminated.
In this case, the biological denitrification treatment facility 13 has a capacity corresponding to the nitrogen load that can be treated with the amount of nutrients (BOD amount) contained in the digested sludge, and the rest is used as the second biological denitrification treatment facility. It is efficient if it is processed.

FIG. 6 shows a schematic flow of the organic waste processing apparatus according to the second embodiment. Hereinafter, in the second embodiment and the third embodiment, detailed description of the configuration substantially similar to that of the first embodiment will be omitted.
The present Example 2 is provided with a solid-liquid separation device 14 at the subsequent stage of the biological denitrogenation treatment facility 13 and supplies the separation liquid 25 obtained by the solid-liquid separation device 14 to the advanced treatment facility 15, At least a part of the separated sludge 26 is supplied to the solubilization facility 30 and the other part is supplied to the sludge treatment facility 16.
The solubilized sludge 23 obtained by the solubilization equipment 30 is returned to the adjustment tank 11 or the methane fermentation tank 12.

The solubilization facility 30 has the same configuration as that of the first embodiment, but FIG. 7 shows a configuration that is particularly preferably used in this embodiment. As shown in the figure, the solubilization equipment 30 has a configuration in which a bead mill 30A that mechanically shears and frictions the separated sludge 26 and a heating device 30B are arranged in series.
In the bead mill 30A, a shaft 138 connected to the motor 130 is inserted in a horizontal cylinder, and a stirring blade provided at a predetermined interval on the shaft 138 rotates, so that The accommodated beads 140 having a diameter of several tens to several hundreds of μm flow. The separated sludge 26 introduced into the bead mill 30A is ground between the flowing beads 140, and the solid matter is finely pulverized and dispersed to be colloidalized.
The colloidal sludge is introduced into the heating device 30B and heated to obtain a low-molecular-weight solubilized solubilized sludge 23.

According to the present embodiment, since the sludge 26 concentrated by the solid-liquid separator 14 is solubilized, the amount of liquid to be solubilized can be reduced, and solubilization equipment power can be reduced.
Further, in the solubilization facility 30, soluble nitrogen such as ammonia nitrogen and soluble phosphorus such as phosphate phosphorus are eluted with sludge solubilization, but this occurs in the sludge treatment facility 16. By returning the separated liquid to the methane fermenter 12 or the biological denitrification treatment facility 13, there is no possibility that the separated liquid will flow into the advanced treatment or be discharged without being treated.

FIG. 8 shows a schematic flow of the organic waste processing apparatus according to the third embodiment.
In the third embodiment, in addition to the configuration of the first embodiment, a solid-liquid separation device 19 is provided in the previous stage of the adjustment tank 11.
The organic waste 20 is solid-liquid separated by the solid-liquid separation device 19 to obtain a separation liquid 29 and separation sludge. Then, the separation sludge is introduced into the adjustment tank 11, and the separation liquid 29 is biologically separated. It introduces into the denitrification processing equipment 13 and biologically denitrifies with the digested sludge 21 discharged from the methane fermentation tank 12.
As another configuration, a liquid waste 40 having a small solid content together with the digested sludge 21 may be input to the biological denitrification equipment 13.

According to the present embodiment, by providing the solid-liquid separation device 19, the load of water flowing into the methane fermentation tank 12 can be reduced, so that the methane fermentation tank 12 can be made compact. Moreover, in biological denitrification treatment, by introducing the liquid waste 40 or the separation liquid 29, the BOD component contained therein can be used as a nutrient source during denitrification, and nutrition such as methanol The external addition amount of the source can be reduced or eliminated.
In addition, you may make it introduce | transduce the said liquid waste 40 or the separation liquid 29 into the 2nd biological denitrification processing facility described in the said Example 1. FIG.

  The present invention can perform methane fermentation and biological denitrification with high efficiency and can reduce the volume of sludge. Therefore, organic sewerage treatment, human waste treatment, septic tank sludge treatment, livestock wastewater It can be effectively applied to any treatment such as wastewater treatment, fishery processing wastewater treatment, washing wastewater treatment, and factory wastewater treatment.

It is a flowchart which shows the outline of the processing system which concerns on Example 1 of this invention. It is a schematic block diagram which shows an example of the solubilization installation of a present Example. It is a figure which shows the specific apparatus structure of the solubilization installation of a present Example. It is a schematic sectional drawing which shows the ozone generator used for the solubilization installation of FIG. It is a schematic block diagram which shows the cavitation apparatus used for the solubilization installation of FIG. It is a flowchart which shows the outline of the processing system which concerns on Example 2 of this invention. It is a schematic block diagram which shows an example of the solubilization installation of FIG. It is a flowchart which shows the outline of the processing system which concerns on Example 3 of this invention. It is a flowchart which shows the outline of the conventional methane fermentation processing system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Adjustment tank 12 Methane fermentation tank 13 Biological denitrification processing equipment 14 Solid-liquid separator 15 Advanced processing equipment 16 Sludge processing equipment 20 Organic waste 23, 24 Solubilized sludge 30 Solubilization equipment 30A Colloidalization process (ozone oxidation) Equipment, bead mill)
30B Liquefaction process (cavitation equipment, heating equipment)
30C Reservoir 40 Liquid waste

Claims (14)

In a method for treating organic waste, comprising: a methane fermentation process for methane fermentation of organic waste; and a biological denitrification process for biologically denitrifying digested sludge produced by the methane fermentation. ,
A solubilization process for obtaining a solubilized sludge by solubilizing a biological treatment liquid from the biological denitrification process is provided, and at least a part of the solubilized sludge is obtained from the methane fermentation process or the methane fermentation process. A method for treating organic waste, which is returned upstream.   The said solubilization process consists of the colloidalization process which mainly colloidizes the said biological treatment liquid, and the liquefaction process which mainly liquefies this colloidalization process liquid, The characterized by the above-mentioned. Of organic waste.   In the solubilization step, the biological treatment liquid is colloided by ozone oxidation in the colloidalization step, and cavitation is generated in the colloidal treatment liquid in the liquefaction step to be liquefied. The method for treating organic waste according to claim 2, wherein: A method for treating organic waste comprising a solid-liquid separation step for obtaining a separated liquid and separated sludge by solid-liquid separation of at least a part of the solubilized sludge,
A second biological denitrogenation that biologically denitrifies the solubilized sludge or the solid-liquid separation solution between the solubilization step and the solid-liquid separation step or after the solid-liquid separation step. 3. A method for treating organic waste according to claim 1, further comprising a treatment step.   A solid-liquid separation step for obtaining a separation liquid and separated sludge by solid-liquid separation of the biological treatment liquid is provided after the biological denitrification treatment step, and the separated sludge is introduced into the solubilization step. The organic waste processing method according to claim 1.   A solid-liquid separation step for obtaining a separated liquid and separated sludge by solid-liquid separation of organic waste is provided before the methane fermentation step, and the separated sludge is introduced into the methane fermentation step, The organic waste treatment method according to claim 1, wherein the organic waste treatment method is introduced into a chemical denitrification treatment step.   The method for treating organic waste according to claim 1, wherein liquid waste with a low solid content is introduced into the biological denitrification step, and the liquid waste is treated together with the digested sludge. . Organic waste treatment equipment comprising: a methane fermentation apparatus for methane fermentation of organic waste; and a biological denitrogenation treatment apparatus for biologically denitrifying digested sludge discharged from the methane fermentation apparatus In
There is provided a solubilization device for obtaining a solubilized sludge by solubilizing a biological treatment liquid discharged from the biological denitrification treatment device, and at least a part of the solubilized sludge is used as the methane fermentation device or the methane An organic waste treatment facility comprising a solubilized sludge return line for returning upstream from the fermenter.   9. The solubilizing apparatus comprises a colloiding means for mainly colloiding the biological treatment liquid and a liquefaction means for mainly liquefying the colloidal treatment liquid. Organic waste processing equipment.   In the solubilization apparatus, the biological treatment liquid is colloided by ozone oxidation by the colloid means, and cavitation is generated in the colloid treatment liquid by the liquefaction means to liquefy. The organic waste treatment facility according to claim 8 or 9, characterized in that An organic waste treatment facility equipped with a solid-liquid separation device that separates at least a part of the solubilized sludge to obtain a separated liquid and separated sludge,
A second biological denitrification apparatus for biologically denitrifying the solubilized sludge or the separated liquid between the solubilizer and the solid-liquid separator or at the subsequent stage of the solid-liquid separator. 10. The organic waste treatment facility according to claim 8 or 9, wherein:   A solid-liquid separation device for obtaining a separated liquid and separated sludge by solid-liquid separation of the biological treatment liquid is provided at a subsequent stage of the biological denitrification treatment apparatus, and the separated sludge is introduced into the solubilizer. The organic waste processing facility according to claim 8.   A solid-liquid separation device is provided in the preceding stage of the methane fermentation apparatus to obtain a separated liquid and separated sludge by solid-liquid separation of organic waste, and the separated sludge is introduced into the methane fermentation apparatus, and the separated liquid is introduced into the biological organism. The organic waste treatment facility according to claim 8, which is introduced into a chemical denitrification treatment apparatus. 9. The organic waste according to claim 8, wherein the biological denitrification apparatus is provided with a liquid waste input line having a low solid content, and the liquid waste is treated together with the digested sludge. Processing equipment.

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