JP4667909B2 - Organic waste treatment method and equipment - Google Patents

Description

  The present invention relates to a technology for biological treatment of organic waste, and in particular, solubilization treatment even for high-concentration organic waste containing a large amount of organic solids such as garbage, food processing residues, and livestock manure. It is related with the processing method and processing equipment of the organic waste which can biologically process efficiently by providing, and can achieve sludge volume reduction.

2. Description of the Related Art Conventionally, biological treatment has been widely used as a method for treating organic waste because it can be treated at a low environmental load and at a relatively low cost. Biological treatment is a method of decomposing and removing pollutants in organic waste by the action of microorganisms, and examples thereof include an activated sludge method, a methane fermentation method, and a biological denitrification method.
FIG. 7 shows a general treatment process using biological treatment. In this treatment process, the SS contained in the organic waste 20 in the biological treatment facility 12 is firstly obtained after crushing / removing contaminants of the large-diameter organic waste 20 in the pretreatment facility 11. The biological treatment liquid 21 is obtained by decomposing and removing BOD and the like. Then, the biological treatment liquid 21 is solubilized by the solubilization equipment 13, and at least a part of the solubilized sludge 23 is returned to the biological treatment equipment 12 or the pretreatment equipment 11. The other part of the solubilized sludge 21 is solid-liquid separated by the solid-liquid separator 14, the solid-liquid separator 24 is agglomerated and separated by the addition of a flocculant by the agglomerator 16, and the agglomerated separator 26 is activated carbon Advanced treatment such as adsorption is performed and discharged as a treatment liquid 28. On the other hand, the solid-liquid separation sludge 25 and the agglomerated separation sludge 27 are introduced into the sludge treatment facility 17 and subjected to treatment such as incineration and composting.

In the treatment process including such biological treatment, the amount of sludge generated is large, the size of the sludge treatment facility is increased, and the treatment cost is increased, so that the volume of sludge is required to be reduced. Therefore, a method for reducing the amount of sludge generated by solubilizing the biological treatment solution after biological treatment has been proposed and put to practical use. The solubilization treatment is intended to reduce the sludge volume by reducing the molecular weight of the organic matter in the digested sludge by methods such as ozone oxidation, heating, and alkali addition, and improving the organic matter decomposition rate in the biological treatment.
For example, in Patent Document 1 (Japanese Patent Laid-Open No. 9-122682), sewage is first subjected to solid-liquid separation in a sedimentation basin, and the separated organic SS is biologically treated by an activated sludge method. Disclosed is a sewage treatment method for obtaining a biological treatment liquid by solid-liquid separation. In this treatment method, after subjecting raw sludge separated in a first sedimentation basin and biological sludge extracted from the biological treatment to methane fermentation, Ozone 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, in biological treatment with conventional solubilization, ammonia nitrogen is produced in the process of sludge solubilization, increasing the ammonia load in the methane fermentation tank and the load of pollutants flowing into the biological denitrification equipment. However, there is a risk of causing processing difficulties.
Also, in the process of sludge solubilization, soluble phosphorous phosphorus is generated, and in biological treatment and coagulation separation equipment, the phosphorus load increases, the equipment becomes larger and the amount of coagulant used increases. There is also.
Furthermore, although the amount of sludge generation can be reduced as an effect of solubilization, there is also a problem that the aggregate sludge increases.
Therefore, in view of the above-mentioned problems of the prior art, the present invention is an organic material that enables sludge volume reduction without increasing the ammonia and phosphorus loads to the biological treatment facility due to the inflow of the treatment liquid containing the solubilizing component. An object is to provide a waste treatment method and treatment equipment.

Therefore, in order to solve such problems, the present invention provides a biological treatment process for biologically treating organic waste as a reference invention, and a solubilization process for solubilizing a biological treatment solution after biological treatment to obtain a solubilized sludge. And a method for treating organic waste, wherein at least a part of the treatment liquid containing the solubilized component after the solubilization step is returned to the biological treatment step or upstream from the biological treatment step. In
In the solubilization step, an invention is proposed in which hypochlorous acid is supplied to the solubilized sludge so that the nitrogen component is removed by the hypochlorous acid and the solubilization is promoted.

This reference invention, the organic material contained in the biological treatment liquid by the solubilization step a low molecular weight, at least a portion of the treatment liquid containing a low molecular weight was solubilizing component, the biological treatment process, or the organism Biological treatment is efficiently performed from the configuration of returning to the upstream side from the treatment process, and the amount of sludge generated can be reduced. The treatment liquid containing the solubilized component refers to a treatment liquid discharged from a treatment step arranged on the downstream side of the solubilization step such as the solubilized sludge and a separated liquid obtained by solid-liquid separation of the solubilized sludge. The biological treatment is a treatment for decomposing and removing contaminants in the treatment liquid by the action of microorganisms, and examples thereof include activated sludge treatment, methane fermentation treatment, biological denitrification treatment, and the like.
Further, according to this reference invention, because the solubilizing sludge is configured to supply the hypochlorite, ammonia nitrogen contained in the biological treatment was decomposed by reaction with hypochlorous acid, nitrogen It can be rendered harmless as a gas, and solubilization is promoted by the oxidizing action of hypochlorous acid.
Furthermore, when the biological treatment step is methane fermentation treatment, the solubilized treatment liquid from which ammonia nitrogen has been removed is returned to the methane fermentation tank, so that the ammonia nitrogen concentration in the methane fermentation tank is reduced by dilution, Ammonia inhibition can be prevented.
Furthermore, when the biological treatment step is nitrification denitrification treatment, the solubilized treatment liquid from which ammonia nitrogen has been removed is returned to the nitrification denitrification treatment facility, so that the nitrogen load in biological treatment can be reduced, and C By increasing the / N ratio, the amount of nutrients such as methanol added can be reduced.

And as this invention concerning Claim 1 , it comprises the biological treatment process which carries out biological treatment of organic waste, and the solubilization process which solubilizes the biological treatment liquid after the biological treatment, and obtains solubilized sludge, In the method for treating organic waste, wherein at least a part of the treatment liquid containing the solubilized component after the solubilization step is returned to the biological treatment step or the upstream side of the biological treatment step.
A solid-liquid separation step for separating the solubilized sludge into a solid and a liquid to obtain a separated liquid and a separated sludge; and a nitrogen removing step for removing nitrogen by supplying hypochlorous acid to the separated liquid. At least a part of the treated liquid is returned.
According to the present invention, the same effect as described above can be obtained, and a separated liquid having a low SS concentration obtained by solid-liquid separation of the solubilized sludge is returned to the biological treatment process or upstream from the biological treatment process. Therefore, it is possible to reduce the burden of biological treatment.

In these inventions, the hypochlorous acid is preferably generated by electrolyzing a chlorine-containing solution (see claim 2). The chlorine-containing solution may be a solution supplied from the outside, but is preferably the solubilized sludge or the solid-liquid separation liquid.
Thus, by electrolyzing the solubilized sludge or the separated liquid to generate hypochlorous acid, it is not necessary to supply hypochlorous acid from the outside, and the substance contained in the treatment target is effectively used. Can be used, leading to cost reduction.

Furthermore, in these inventions, a phosphorus recovery step for separating and recovering a phosphorus component in the treatment liquid is provided on the downstream side of the step of supplying the hypochlorous acid such as the solubilization step or the nitrogen removal step. may be the (claim 3 reference) in this case the phosphorus recovery process, it is preferable that a step of recovering phosphorus by iron electrolysis.
In this way, by insolubilizing or recovering phosphoric acid phosphorus generated during the treatment process, it is possible to downsize or eliminate the subsequent agglomeration separation equipment, and by supplying hypochlorous acid, free chlorine, This is because even when bound chlorine remains, it is partially rendered harmless by the reducing action of iron ions.

Furthermore, in the above invention,
A phosphorus recovery step for separating and recovering a phosphorus component in the treatment liquid is provided on the subsequent stage side of the solubilization step.
According to the present invention, it is possible to downsize or eliminate the subsequent aggregating and separating equipment by insolubilizing or recovering the generated phosphorous phosphorus by the solubilization step.

Furthermore, a solid-liquid separation step is performed between the solubilization step and the phosphorus recovery step to obtain a separated liquid and separated sludge by solid-liquid separation of the solubilized sludge, and the separation liquid is added to the phosphorus recovery step. It is characterized by introducing it.
Thereby, since the separation liquid having a low SS concentration is introduced into the phosphorus recovery step, the phosphorus recovery efficiency is improved.

In addition, a biological treatment apparatus for biologically treating organic waste and a solubilization apparatus for obtaining a solubilized sludge by solubilizing the biological treatment liquid after the biological treatment, and the solubilized component after the solubilization In an organic waste treatment facility comprising a return line for returning at least a part of the treatment liquid containing the biological treatment device or the upstream side of the biological treatment device,
A solid-liquid separation device that separates the solubilized sludge into solid and liquid to obtain a separated liquid and separated sludge; and a nitrogen removing device that removes nitrogen from the separated liquid. Hypochlorous acid supply means for supplying chlorous acid is provided.
Furthermore, the hypochlorous acid supply means comprises an electrolytic cell into which a chlorine-containing solution is introduced, and an electrolytic device having an anode and a cathode immersed in the solution in the electrolytic cell and connected to a power source, It is preferable that electrolysis is performed by energizing between the cathodes to generate the hypochlorous acid.
Since at least a part of the electrolytic treatment liquid is returned to the biological treatment apparatus or the upstream side of the biological treatment apparatus, the H ₂ gas produced by the cathode as a by-product in the electrolytic cell is biological It can be used as a nutrient source for denitrification or as a raw material for generating methane gas in the treatment.
In these processing facilities, a phosphorus recovery device for separating and recovering phosphorus components in the processing solution is provided on the rear side of the device (solubilization device or nitrogen removal device) provided with the hypochlorous acid supply means. In this case, the phosphorus recovery device is preferably an iron electrolysis device.

    Further, a solid-liquid separation device is provided between the solubilizer and the phosphorus recovery device to separate the solubilized sludge by solid-liquid separation to obtain a separated liquid and separated sludge, and the separated liquid is introduced into the phosphorus recovery device. It is characterized by having a configuration to do.

Furthermore, the phosphorus recovery device is at least one of an iron electrolysis device, a MAP (magnesium ammonium phosphate) recovery device, and a hydroxyapatite recovery device.
This is because when the biological treatment apparatus is a methane fermentation tank and an iron electrolysis apparatus is used as the phosphorus recovery apparatus, it is returned to the methane fermentation tank in a state where iron is mixed into the solubilized sludge. Generation of hydrogen sulfide in the tank can be suppressed. Furthermore, the insolubilized phosphorus is finally put into the sludge treatment facility, but when composting is performed in the sludge treatment facility, high-quality compost rich in phosphorus and iron, which are fertilizer components, can be produced.
Iron ions also have an effect of reducing COD and chromaticity, and can be expected to reduce the amount of coagulant used in the coagulation separator and the amount of activated carbon used in the advanced treatment device.
Since at least a part of the treatment liquid in the iron electrolysis tank is returned to the biological treatment apparatus or the upstream side of the biological treatment apparatus, in the iron electrolysis apparatus, the H ₂ gas produced at the cathode as a by-product is It can be used as a nutrient source for denitrification or a raw material for methane gas generation in biological treatment.
Moreover, when MAP recovery and hydroxyapatite recovery are performed, valuable resources can be recovered.

As described above, according to the present invention, problems caused by providing solubilization facilities can be solved, and biological treatment efficiency and sludge volume reduction can be achieved.
Moreover , according to this reference invention, since it was set as the structure which supplies hypochlorous acid to a solubilization process (apparatus), while solubilization is accelerated | stimulated, ammonia nitrogen generated by solubilization can be removed, and biological Ammonia inhibition or load increase in the treatment can be avoided.
On the other hand , according to the present invention, nitrogen removal is performed on the downstream side of the solubilization step (apparatus), so that ammonia nitrogen generated by solubilization can be removed in the same manner, and ammonia inhibition or increase in load in biological treatment is avoided. it can.
Furthermore, according to the present invention, phosphorus recovery is performed on the latter stage side of the solubilization step (apparatus), so that an increase in phosphorus load due to solubilization is prevented and sludge volume reduction is realized. be able to.

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 treatment targets of this embodiment include organic waste such as food waste, food processing residues, livestock waste, and sludge generated by water treatment such as sewage treatment. Since it is a structure provided with the solubilization equipment, it is particularly preferably used in the treatment of high-concentration organic waste.
1 is a flowchart showing an outline of a processing facility according to Embodiment 1 of the present invention, FIG. 2 is a configuration diagram showing an example of a hypochlorous acid supply means of FIG. 1, and FIG. 3 is related to Embodiment 2 of the present invention. FIG. 4 is a flowchart showing the outline of the processing facility according to the third embodiment of the present invention, FIG. 5 is a block diagram showing an example of the phosphorus recovery facility of FIG. 4, and FIG. It is a flowchart which shows the outline of the processing equipment which concerns on Example 4.

  As shown in FIG. 1, the organic waste treatment facility according to the first embodiment includes a pretreatment facility 11 into which the organic waste 20 is introduced from the upstream to the downstream of the line, and the pretreated organic waste. A biological treatment facility 12 that introduces waste and performs biological treatment to obtain a biological treatment liquid 21, a solubilization equipment 13 that solubilizes the biological treatment liquid 21 to obtain a solubilized sludge 23, and the solubilized sludge Solid-liquid separation device 14 that obtains solid-liquid separation liquid 24 and solid-liquid separation sludge 25 by solid-liquid separation, and agglomeration separation device that agglomerates and separates solid-liquid separation liquid 24 to obtain agglomeration separation liquid 26 and aggregation separation sludge 27 15, an advanced treatment device 16 that obtains a treatment liquid 28 by advanced treatment of the flocculated separation liquid 26, and a sludge treatment facility 17 that treats the solid-liquid separation sludge 25 and the flocculated separation sludge 27. .

The pretreatment facility 11 includes a crushing means for crushing a large-diameter organic waste, a sorting means for removing impurities, and the like.
The biological treatment facility 12 is a facility that decomposes organic substances by the action of microorganisms and removes SS, BOD, nitrogen components and the like contained in the organic waste 20, and is an activated sludge system, methane fermentation system, biological Any method such as a denitrification method can be applied.
The solubilization equipment 13 may be any method such as physicochemical solubilization, biological solubilization, mechanical solubilization, etc., for example, ozone oxidation means, ultrasonic means, heating means including hydrothermal, lytic enzyme supply Examples include means, cavitation generating means, oxidizing agent adding means, electrolysis means, alkaline agent adding means, mechanical shearing / friction means, and the like, and means having at least one or a combination of these is provided. Preferably, the solubilization equipment 13 may include two steps including a colloidalization step of the biological treatment liquid 21 and a liquefaction step of the colloidal substance, and more preferably ozone is added in the colloidalization step. After oxidization and colloiding the biological treatment liquid, it may be liquefied by generating cavitation in the colloidal substance in the liquefaction step.

The solid-liquid separation device 14 is a device that separates the solubilized sludge 23 into a solid-liquid separation liquid 24 and a solid-liquid separation sludge 25, and includes a gravity sedimentation method, a centrifugal separation method, a membrane separation method, a coagulation separation method, and a flotation method. A separation method or the like is used.
The aggregating / separating device 15 is a device that settles and removes soluble pollutants by adding an aggregating agent. As the aggregating agent, an inorganic aggregating agent, a polymer aggregating agent, or the like is used.
The advanced treatment device 16 may be an activated carbon adsorption tower or the like, and may be installed as necessary when the separated liquid 26 after the coagulation and separation does not meet the discharge standard.
The sludge treatment facility 17 is a facility for performing dehydration, drying, incineration, composting and the like of the separated sludge 26.

Furthermore, as a characteristic configuration of the present embodiment, hypochlorous acid supply means 30 for supplying hypochlorous acid to the solubilization equipment 13 is provided (reference invention) .
The hypochlorous acid supply means 30 includes a storage tank that stores hypochlorous acid, and a pump that supplies the stored hypochlorous acid to the solubilization facility 13 as appropriate in predetermined amounts. Alternatively, an electrolysis apparatus may be provided, and hypochlorous acid generated by electrolyzing a chlorine-containing solution in the electrolysis apparatus may be supplied to the solubilization equipment 13 by a predetermined amount. The chlorine-containing solution may be a solution supplied from the outside, but preferably the solubilized sludge is extracted from the solubilizing equipment 13 and introduced into the electrolyzer.
An example of the electrolyzer is shown in FIG. As shown in the figure, an electrolysis apparatus 31 constituting the hypochlorous acid supply means 30 is disposed opposite to an electrolysis tank 32 that receives the chlorine-containing solution and to be immersed in the solution of the electrolysis tank 32. And an electrode composed of an anode 33 and a cathode 34, and a power supply device 35 connected to the electrodes.

And as a typical reaction in each electrode, the following reactions are caused by chlorine ions, water and nitrate ions contained in the solution.
(Anode) 2Cl ⁻ → Cl ₂ + 2e ⁻
Cl ₂ + H ₂ O → HClO + HCl
(Cathode) NO ₃ ⁻ + 6H ₂ O + 8e → NH ₃ + 9OH ⁻
2H ₂ O + 2e ⁻ → 2OH ⁻ + H ₂ ↑
Chlorine is generated at the anode, and the chlorine reacts with water to produce hypochlorous acid (HClO) having a strong oxidizing power. On the other hand, when nitrate ions are contained in the solution, the cathode is reduced to ammonia. When nitrate ions are not included, hydrogen is generated by electrolysis of water. The solution containing the hypochlorous acid 36 is introduced into the solubilization equipment 13, and ammonia nitrogen present in the solubilized sludge is reacted by the following reaction formula and removed as nitrogen gas in the solubilization equipment 13. The
2NH ₃ + 3HClO → N ₂ ↑ + 3HCl + 3H ₂ O
The hypochlorous acid 36 also has an action of promoting solubilization by its oxidizing action.
In the electrolysis apparatus 31, it is preferable to maintain the electrolysis efficiency by applying a reverse voltage every predetermined time or by stopping the treatment and washing in order to remove the substances adhering to the electrode.
When the solubilized sludge drawn out from the solubilization equipment 13 is introduced into the electrolysis apparatus 31, dilution water, the separation liquid 24 from the subsequent solid-liquid separation apparatus 14, or the separation liquid 26 from the coagulation separation apparatus 15. For example, the solubilized sludge may be diluted and introduced.

About the processing equipment which has the above composition, the operation is explained with a processing method.
First, the organic waste 20 is put into the pretreatment facility 11, and after pretreatment such as removal of impurities, crushing / sorting, etc. is performed in the pretreatment facility 11, the organic waste 20 is supplied to the biological treatment facility 12. The biological treatment liquid 21 is obtained by removing SS, BOD, nitrogen components and the like in the waste by the decomposition action of microorganisms in the treatment facility 12. Then, the biological treatment liquid 21 is introduced into the solubilization equipment 13, the treatment liquid is solubilized by various solubilization means in the solubilization equipment 13, and the solubilization equipment 13 is supplied by the hypochlorous acid supply means 30. Hypochlorous acid is supplied, and the low molecular weight of the organic matter is promoted by the oxidizing action of the hypochlorous acid and nitrogen is removed to obtain the solubilized sludge 23.
At least a part of the solubilized sludge 23 is returned to the biological treatment facility 12 or the pretreatment facility 11, and the other part is introduced into the solid-liquid separator 14 to obtain a separation liquid 24 and a separation sludge 25. The separation liquid 24 is flocculated and separated by adding a flocculant in the flocculation / separation device 15 to obtain a separation liquid 26 and sludge 27. The separation liquid 27 is subjected to advanced processing by the advanced processing apparatus 16 and discharged as a purified processing liquid 28. On the other hand, the separated sludges 25 and 27 are supplied to the sludge treatment facility 17 where the sludge treatment facility 17 performs incineration, composting, and the like.

According to the present embodiment, by supplying hypochlorous acid 36 to the solubilizing equipment 13, the generated ammoniacal nitrogen can be decomposed by reaction with hypochlorous acid 36 and rendered harmless as nitrogen gas. In addition, solubilization can be further promoted by the oxidizing action of hypochlorous acid 36.
Further, when methane fermentation is performed in the biological treatment facility 12, the solubilized sludge 23 from which ammonia nitrogen has been removed by reaction with hypochlorous acid 36 is returned to the methane fermentation tank. The nitrogen concentration is reduced by dilution, and ammonia inhibition can be prevented.
When the nitrification / denitrification treatment is performed in the biological treatment facility 12, the nitrogen load in the nitrification / denitrification treatment facility can be reduced by returning the solubilized sludge 23 from which ammonia nitrogen has been removed to the nitrification / denitrification treatment facility. As the C / N ratio increases, the amount of nutrients such as methanol can be reduced.
As described above, according to the present embodiment, by supplying hypochlorous acid 36 to the solubilization equipment 13, the volume of sludge can be reduced without increasing the ammonia load in the biological treatment equipment 12 due to the inflow of the solubilization sludge 23. Can be realized.

FIG. 3 shows a schematic flow of the organic waste processing facility 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.
In the treatment facility according to the second embodiment, the pretreatment facility 11 into which the organic waste 20 is introduced from the upstream to the downstream of the line and the pretreated organic waste are introduced to perform biological treatment. A biological treatment facility 12 for obtaining a biological treatment liquid 21, a solubilization facility 13 for solubilizing the biological treatment liquid 21 to obtain a solubilized sludge 23, and a solid-liquid separation liquid 24 by solid-liquid separation of the solubilized sludge. The solid-liquid separation device 14 for obtaining the solid-liquid separation sludge 25, the nitrogen removal device 18 for removing nitrogen from the solid-liquid separation liquid 24, and the coagulation separation liquid 26 and the aggregation separation sludge 27 by coagulating and separating the nitrogen-removed treatment liquid 29. A flocculating / separating device 15 for obtaining a slag, an advanced processing device 16 for processing the flocculated / separated liquid 26 to obtain a treatment liquid 28, a sludge treatment facility 17 for treating the solid-liquid separation sludge 25 and the flocculated / separated sludge 27, And exhausted from the nitrogen removing device 18 At least a portion of the processing liquid 29 to be, a configuration that is returned to the biological treatment facility 12 or the pre-treatment facility 11.

The nitrogen removing device 18 includes hypochlorous acid supply means 30. The hypochlorous acid supply means 30 may have substantially the same configuration as that of the above-described embodiment, and may be configured to add hypochlorous acid from the outside. The hypochlorous acid supply means 30 includes an electrolysis apparatus, and contains a chlorine-containing solution, preferably the nitrogen. A part of the processing liquid drawn out from the removing device 18 may be introduced into the electrolysis device, electrolyzed to generate hypochlorous acid, and returned to the nitrogen removing device 18.
The solid-liquid separation liquid 24 that has been solid-liquid separated by the solid-liquid separation device 14 is introduced into the nitrogen removal device 18, and ammonia nitrogen is converted into nitrogen gas by supplying hypochlorous acid 36 by the nitrogen removal device 18. Removed and rendered harmless.
In this way, by adopting a configuration in which the solid-liquid separation liquid 24 is introduced into the nitrogen removing device 18, the separation liquid having a low SS concentration is returned to the biological treatment, so that it is possible to reduce the burden of the biological treatment. .

FIG. 4 shows a schematic flow of the organic waste processing facility according to the third embodiment.
In the treatment facility according to the third embodiment, the pretreatment facility 11 into which the organic waste 20 is introduced from the upstream to the downstream of the line and the pretreated organic waste are introduced to perform biological treatment. A biological treatment facility 12 for obtaining a biological treatment liquid 21, a solubilization facility 13 for solubilizing the biological treatment liquid 21 to obtain a solubilized sludge 23, a phosphorus recovery facility 40 for recovering phosphorus from the solubilized sludge, A solid-liquid separation device 14 that obtains a solid-liquid separation liquid 24 and a solid-liquid separation sludge 25 by solid-liquid separation of the treatment liquid 22 from which the components have been removed, and a coagulation separation liquid 26 by aggregating and separating the solid-liquid separation liquid 24. The flocculating / separating device 15 for obtaining the flocculated / separated sludge 27, the advanced processing device 16 for performing the advanced treatment of the flocculated / separated liquid 26 to obtain the treatment liquid 28, the sludge for treating the solid / liquid separated sludge 25 and the flocculated / separated sludge 27 Treatment facility 17, and the phosphorus recovery facility At least a portion of the resulting treated liquid 22 at 0 are configured to return to the biological treatment facility 12 or the pre-treatment facility 11.

The phosphorus recovery facility 40 is a facility for insolubilizing or recovering phosphate phosphorus generated in the solubilization facility 13 provided on the front side. As the phosphorus recovery equipment 40, any method such as a biological method, a coagulation precipitation method, a crystallization method, an adsorption method and the like can be used. In particular, the coagulation precipitation method or the crystallization method is preferable in this embodiment. .
As the agglomeration precipitation method, a known aggregating agent such as an inorganic aggregating agent such as a sulfate band and iron (III) chloride, or a polymer aggregating agent is used alone or in combination. Separate by settling. Preferably, the phosphorus recovery facility 40 is provided with an iron electrolysis device, and the phosphorous phosphorus is aggregated by the eluted iron ions.
As the crystallization method, phosphate ion (PO ₄ ³⁻ ) in the treatment liquid is crystallized and separated as hydroxyapatite (Ca ₅ (PO ₄ ) ₃ OH) and recovered as a crystallized product (reference) Document: JP-A-11-309464), or a method in which phosphate ions in a treatment liquid are crystallized and separated as MAP (magnesium ammonium phosphate; MgHPO ₄ ), and recovered as a crystallized product (reference document; No. 2004-290862).

Here, an example of a specific configuration of the phosphorus recovery facility 40 is shown in FIG. As shown in the figure, the phosphorus recovery facility 40 is composed of an iron electrolyzer 41, a coagulant tank 46, and a coagulation sedimentation tank 47, and the iron electrolyzer 41 receives the solubilized sludge 23. An electrolytic cell 42, an electrode composed of an anode 43 and a cathode 44 disposed so as to be immersed in the solubilized sludge 23 in the electrolytic cell 42, and a power supply device 45 connected to the electrode. ing. At this time, the anode 43 is an iron electrode. It is preferable that the solubilized sludge 23 introduced into the electrolytic cell 42 is diluted with dilution water or a separation liquid 24 from the solid-liquid separation device 14 and a separation liquid 26 from the coagulation sedimentation device 15. The iron ions (Fe ²⁺ , Fe ³⁺ ) eluted by the iron electrolyzer 41 react with soluble phosphate ions to insolubilize as iron phosphate (Fe ₃ (PO ₄ ) ₂ , FePO ₄ ), They are separated in the coagulation sedimentation tank 46.
On the other hand, other coagulant addition means different from the iron electrolysis apparatus 41 may be used in combination, and the coagulant stored in the coagulant tank 46 may be appropriately added to the coagulation sedimentation tank 46.

According to the present embodiment, the phosphorus recovery facility 40 is provided, and the phosphorous phosphorus generated by the solubilization facility 13 is insolubilized or recovered, thereby making it possible to downsize or eliminate the subsequent aggregation / separation device 15. In addition, the solid-liquid separator 14 and the coagulation separator 15 can be unified.
In addition, when the biological treatment facility 12 is a methane fermentation tank and the iron electrolysis apparatus 41 is used as the phosphorus recovery facility, the iron is mixed into the solubilized sludge 23 and returned to the methane fermentation tank. Generation of hydrogen sulfide in the methane fermentation tank can be suppressed. In this case, the insolubilized phosphorus is finally fed into the sludge treatment facility, but when composting is performed in the sludge treatment facility, compost containing abundant phosphorus and iron, which are fertilizer components, can be produced.
Furthermore, when MAP recovery and hydroxyapatite recovery are performed, valuable resources can be recovered.
Furthermore, when iron is added as a solid coagulant, iron may be consumed by organic matter. However, when the iron electrolysis is performed, it is added as iron ions, so that soluble phosphate ions can be removed. It will be done effectively.
As described above, according to the present embodiment, by providing the phosphorus recovery facility 40, it is possible to prevent the increase in the phosphorus load caused by the solubilization facility 13 and realize the facility capable of reducing the sludge volume. it can.
It goes without saying that the phosphorus recovery facility 40 shown in the embodiment may be applied to the first or second embodiment. At this time, the phosphorus recovery equipment 40 is preferably an iron electrolysis apparatus. As a result, the phosphorous phosphorus generated in the treatment process can be insolubilized or recovered, so that the subsequent agglomeration separation facility can be reduced in size or made unnecessary, and the solubilization facility 13 or the nitrogen removing device 18 can be used. This is because even if free chlorine and bonded chlorine remain due to the supply of hypochlorous acid, it is partially detoxified by the reducing action of iron ions.

FIG. 6 shows a schematic flow of the organic waste processing facility according to the fourth embodiment.
In the treatment facility according to the fourth embodiment, from the upstream to the downstream of the line, the pretreatment facility 11 into which the organic waste 20 is introduced and the pretreated organic waste are introduced to perform biological treatment. A biological treatment facility 12 for obtaining a biological treatment liquid 21, a solubilization facility 13 for solubilizing the biological treatment liquid 21 to obtain a solubilized sludge 23, and a solid-liquid separation liquid 24 by solid-liquid separation of the solubilized sludge. A solid-liquid separation device 14 for obtaining a solid-liquid separation sludge 25; a phosphorus recovery facility 40 for removing phosphorus from the solid-liquid separation liquid 24; and a coagulation separation liquid 26 by coagulating and separating the treatment liquid 22 from which the phosphorus component has been removed. The flocculating / separating device 15 for obtaining the flocculated / separated sludge 27, the advanced processing device 16 for performing the advanced treatment of the flocculated / separated liquid 26 to obtain the treatment liquid 28, the sludge for treating the solid / liquid separated sludge 25 and the flocculated / separated sludge 27 A treatment facility 17, and the solid-liquid separation liquid 24. At least a part has a structure to return to the biological treatment facility 12 or the pre-treatment facility 11.

The configuration of the phosphorus recovery facility 40 is the same as that of the third embodiment.
In the present embodiment, in addition to the same effects as in the third embodiment, solid-liquid separation is performed by the solid-liquid separation device 14, and phosphorus recovery processing is performed on the separation liquid 24 having a low SS concentration. Efficient phosphorus removal and recovery.

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

It is a flowchart which shows the outline of the processing equipment which concerns on Example 1 of this invention. It is a block diagram which shows an example of the hypochlorous acid supply means of FIG. It is a flowchart which shows the outline of the processing equipment which concerns on Example 2 of this invention. It is a flowchart which shows the outline of the processing equipment which concerns on Example 3 of this invention. It is a block diagram which shows an example of the phosphorus collection | recovery installation of FIG. It is a flowchart which shows the outline of the processing equipment which concerns on Example 4 of this invention. It is a flowchart which shows the outline of the processing facility of the conventional organic waste.

DESCRIPTION OF SYMBOLS 11 Pretreatment equipment 12 Biological treatment equipment 13 Solubilization equipment 14 Solid-liquid separation equipment 15 Coagulation separation equipment 16 Advanced treatment equipment 17 Sludge treatment equipment 18 Nitrogen removal equipment 20 Organic waste 30 Hypochlorous acid supply means 31 Electrolysis equipment 36 Next Chlorous acid 40 Phosphorus recovery equipment 41 Electrolyzer 45 Coagulant tank 46 Coagulation sedimentation tank

Claims (10)

A biological treatment process for biologically treating organic waste, and a solubilization process for obtaining a solubilized sludge by solubilizing the biological treatment liquid after the biological treatment, and including a solubilized component after the solubilization process In the method for treating organic waste, wherein at least a part of the treatment liquid is returned to the biological treatment step or to the upstream side of the biological treatment step,
A solid-liquid separation step for separating the solubilized sludge into a solid and a liquid to obtain a separated liquid and a separated sludge; and a nitrogen removing step for removing nitrogen by supplying hypochlorous acid to the separated liquid. A method for treating organic waste, wherein at least a part of the treated liquid is returned.   The method for treating organic waste according to claim 1, wherein the hypochlorous acid is generated by electrolyzing a chlorine-containing solution. A method for treating organic waste according to claim 1 or 2,
A method for treating organic waste, characterized in that a phosphorus recovery step for separating and recovering a phosphorus component in a treatment liquid is provided on the downstream side of the step of supplying hypochlorous acid. The organic waste treatment method according to claim 1 or 2 , wherein a phosphorus recovery step for separating and recovering a phosphorus component in the treatment liquid is provided on a subsequent stage side of the solubilization step. Waste disposal method. A solid-liquid separation step is performed between the solubilization step and the phosphorus recovery step to obtain a separated liquid and separated sludge by solid-liquid separation of the solubilized sludge, and the separation liquid is introduced into the phosphorus recovery step. The organic waste processing method according to claim 4 , wherein the organic waste is treated as described above. A biological treatment apparatus for biologically treating organic waste; and a solubilization apparatus for obtaining a solubilized sludge by solubilizing the biological treatment liquid after the biological treatment, and including the solubilized component after the solubilization In an organic waste treatment facility comprising a return line for returning at least a part of a treatment liquid to the biological treatment device or the upstream side of the biological treatment device,
A solid-liquid separation device that separates the solubilized sludge into solid and liquid to obtain a separated liquid and separated sludge; and a nitrogen removing device that removes nitrogen from the separated liquid. An organic waste treatment facility comprising hypochlorous acid supply means for supplying chlorous acid. The hypochlorous acid supply means comprises an electrolytic cell into which a chlorine-containing solution is introduced, and an electrolytic device having an anode and a cathode immersed in the solution in the electrolytic cell and connected to a power source. The organic waste treatment facility according to claim 6 , wherein electrolysis is performed by energizing in between to generate the hypochlorous acid. The organic waste treatment facility according to claim 6 or 7 ,
An organic waste treatment facility, wherein a phosphorus recovery device for separating and recovering a phosphorus component in the treatment liquid is provided on the rear side of the device provided with the hypochlorous acid supply means. Provided between the solubilizer and the phosphorus recovery device is a solid-liquid separation device that separates the solubilized sludge to obtain a separated liquid and separated sludge, and introduces the separated liquid into the phosphorus recovery device The organic waste treatment facility according to claim 8, wherein: The organic waste treatment according to claim 8 or 9 , wherein the phosphorus recovery device is at least one of an iron electrolysis device, a MAP (magnesium ammonium phosphate) recovery device, and a hydroxyapatite recovery device. Facility.

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