JP2001025795A - Treatment method of sludge and treatment of organic waste water including the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate and recover a phosphorus component in a short time and to reduce the requisite amt. of flocculant when the component is deposited as a solid by applying a high-voltage pulse to the sludge and discharging the component into a liq. phase. SOLUTION: The raw waste water A is introduced into an anaerobic tank 6 and anaerobically digested, and a phosphorus component stored in the body of a microorganism as the granule of polyphosphoric acid is discharged. Subsequently, the treated liq. is sent to an aeration tank 1 provided with an aeration means 11 of an air pump, the org. matter is aerobically decomposed, the phosphorus component is ingested by the microorganism (stored in the body), and then the aerated liq. is separated by a solid-liq. separation means 2 into primary sludge X concentrated in the phosphorus component and primary treated water (a). A high-voltage pulse is impressed on the primary sludge X in a phosphorus discharge tank 3 to discharge the phosphorus component from the microorganism mainly as polyphosphoric acid, and then a relatively small volume of the treated water (b) having a high content of phosphorus component is separated from secondary sludge (z) by a solid-liq. separation means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-cost, high-yield method for treating organic wastewater discharged from a sewage treatment process such as a sewage treatment plant, a human waste treatment plant, or a food factory or a chemical factory. The present invention relates to a method for treating phosphorus that can separate and recover phosphorus components by using the method, and a method for treating organic wastewater employing the treatment method.

[0002]

2. Description of the Related Art As a method for treating organic wastewater, surplus sludge consisting of microbial biomass mainly composed of microbial cells and untreated residual sludge generated by biological digestion of organic wastewater is known. 2. Description of the Related Art A method has been widely adopted in which a treated sludge containing solids is separated into solid and liquid in a sedimentation tank or the like and treated water obtained as a supernatant is appropriately discarded, while excess sludge is treated by dumping in the ocean or land reclamation.

[0003] However, depending on the organic wastewater to be treated, a high content of phosphorus components (ie, orthophosphoric acid (orthophosphoric acid), polyphosphoric acid, phosphate) is contained in the treated water and excess sludge generated by such treatment. , Phosphate esters,
Phosphoproteins, glycerophosphate, phospholipids, etc.) in some cases. Disposal of these is regarded as a direct cause of environmental pollution, and in particular, when treated water containing such a large amount of phosphorus is discharged into lakes and marshes, phytoplankton remarkably grows due to eutrophication of water. Not preferred.

Accordingly, there has been a case in which a method is employed in which the following coagulant is added to the treated water from the precipitation apparatus to reduce the phosphorus component and then the treated water is discharged. In order to perform such a coagulation operation on water, a large-scale processing apparatus must be added, which increases the processing cost, the required time, the required number of personnel, etc., and causes a disadvantage. In addition, the efficiency of aggregation is low, and the removal of the phosphorus component may be insufficiently completed. At present, phosphorus components in excess sludge must be discarded without any means to remove them.

[0005] Incidentally, conventionally known processes for removing phosphorus contained in wastewater include a flocculant addition method, a crystallization dephosphorization method, and an anaerobic-aerobic activated sludge method (sewerage facility planning).・ Design guidelines and explanations (Part 2) 1
994 edition, published by Japan Sewer Association, No. 131-1
See page 36).

The coagulant addition method utilizes the fact that trivalent metal cations such as aluminum ions and iron ions react with orthophosphate ions to form poorly water-soluble phosphates. The flocculant is mixed with the wastewater, and the floc (including biologically derived floc) formed from the hardly soluble phosphate is precipitated and separated. According to this method, an increase in excess sludge of about 5 to 20% has been recognized, and it is hard to say that large-scale disposal of excess sludge containing a large amount of phosphorus component is preferable in recent years, as environmental conservation is being called for.

The crystallization method is based on the formation of hardly soluble hydroxyapatite by the reaction of orthophosphate ions and calcium ions, and is preferable in that it does not involve an increase in excess sludge. Since the conditions required for crystallization must be strictly controlled (for example, removal of crystallization-interfering substances such as carbonate ions by pretreatment, pH adjustment, temperature adjustment, etc.), application is limited and cost increases. It is not a preferable method as a means in wastewater treatment because it includes the cause of inducing.

In the anaerobic-aerobic activated sludge method, microorganisms that have released polyphosphoric acid as orthophosphoric acid in an anaerobic state for energy acquisition accumulate as polyphosphoric acid after excessive intake and metabolism of orthophosphoric acid in an aerobic state. In this method, wastewater is subjected to repeated treatment in an anaerobic tank, an aerobic tank, and a sedimentation basin so that excess sludge contains a phosphorus component and the phosphorus component in the treated water is removed. Although the phosphorus component can be effectively removed from the treated water by this method, the excess sludge is rich in the phosphorus component and contains various other organic components and heavy metal components. And although the phosphorus component may be effectively used for producing fertilizers and phosphorus compounds, for example, it is inevitably discarded in a sludge state mixed with such miscellaneous components.

Therefore, for the purpose of recovering phosphorus from the sludge generated by the biological treatment and effectively using the sludge, the sludge is anaerobically treated to elute the phosphorus component in the sludge, and the eluted phosphorus component is aggregated. A method for adding and recovering an agent has been developed (see JP-A-9-267099), and more recently, an ozone treatment method (see JP-A-9-26999).
No. 4596), an alkali addition method (Japanese Patent Laid-Open No. 8-3).
No. 9096), and a method of recovering phosphorus in sludge by a method of mechanical pulverization (see Japanese Patent Application Laid-Open No. 11-57791).

[0010]

However, in the ozone treatment method, although there are few problems caused by chemicals and wastes, facility costs and running costs are very high, so that it can be practically used from an economical point of view. Absent. According to the alkali addition method, an alkali waste liquid is generated, and further cost is required for treating the waste liquid. According to a method including a step of releasing phosphorus components from microorganisms by exposing sludge to an anaerobic treatment step, phosphorus can be collected and reused at a relatively low cost, Processing time is required, and a considerably large amount of coagulant is required to precipitate the phosphorus component. In the method using mechanical pulverization, a special device such as rotating metal blades at a high speed or rotating beads at a high speed is required, and maintenance of the device requires considerable cost and time.

In recent years, the achievement rates of the environmental standards of COD for lakes, marshes and closed sea areas have been 40% and 65%, respectively.
This is thought to be due to endogenous substances such as blue-green algae and plankton. For this reason,
The Environment Agency consulted the Central Council in February 1999 regarding the total emission control of nitrogen and phosphorus, which causes eutrophication, and a report on these regulations will be made in March 2000. There is a continuing need for a treatment method that efficiently and recyclably recovers the phosphorus component contained in the organic wastewater and that can be implemented at low cost without adversely affecting the environment.

Further focusing on the demand for the phosphorus component,
Currently, more than 900,000 tons (equivalent to more than 10 billion yen) of phosphorus ore are imported from other countries in Japan. However, it is becoming increasingly difficult to extract high-grade phosphate ore from its place of origin due to long-term consumption, and it is not clear whether it can be supplied to Japan in a stable manner in the future. Also,
Currently, about 3,000 tons (equivalent to more than 400 million yen) of polyphosphate are imported to Japan from Asia, Europe and the United States each year, and the amount of this import is increasing year by year. This is because polyphosphoric acid can be a raw material for the production of ATP and for the production of mineral fiber, which is expected to be a substitute for asbestos having carcinogenicity, and tripolyphosphoric acid is a synthetic detergent, detergent, sequestering agent, food It is considered that this is because it is used as a raw material of an additive and in a reagent raw material used for papermaking, dyeing, photographic technology and the like.

Therefore, in order to meet such a high demand in Japan, phosphate (calcium phosphate), which is a main component of phosphate ore, is contained in extremely high purity, or in a state of high purity as polyphosphate, If the phosphorus component derived from organic wastewater is recovered, it will be possible to use phosphorus component, which caused environmental pollution by disposal, very effectively, which will greatly contribute to various industries. It is.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for separating and recovering a phosphorus component efficiently and in a short time in an organic wastewater treatment method. (Coagulant) An object of the present invention is to provide a treatment method that achieves an effect that the required amount can be reduced, and is advantageous in reusing the phosphorus component.

[0015]

Means for Solving the Problems The first invention of the present application for achieving the above object is a method for treating sludge, in which a phosphorus component in the sludge is discharged to a liquid phase by applying a high voltage pulse to the sludge. The gist is a method characterized by the following. According to this method, the effects of radicals, ozone, and shock waves generated by electric discharge during high-voltage pulse processing are combined, and the phosphorus component is mainly released as polyphosphoric acid into the liquid phase. Therefore, it is advantageous in that the amount of a reagent such as a metal salt required for coagulating the phosphorus component is small.

Next, a second invention of the present application is the phosphorous treatment method of the first invention of the present invention, wherein after performing a phosphorus release treatment, the treatment liquid is separated into a solid and a liquid, and the released phosphorus component is added by adding a coagulant. The method further comprises a step of precipitating from a liquid phase. If the precipitate of the phosphorus component is recovered in this way, it can be easily used for producing fertilizers and phosphorus compounds.

According to a third aspect of the present invention, there is provided a method for treating organic wastewater, comprising: (1) an aeration treatment step in which wastewater is subjected to aerobic treatment; and (2) wastewater after aeration treatment is treated with primary treated water and primary sludge. (3) a phosphorus releasing step of applying a high voltage pulse to release a phosphorus component from the separated primary sludge into a liquid phase, and (4) a released phosphorus component. A method for treating organic wastewater, comprising a solid-liquid separation step of separating into secondary treated water and secondary sludge from which phosphorus components have been removed. According to this method, the phosphorus component is accumulated in the microorganisms in the wastewater in the aeration treatment step (1), and this treated water is mixed with the primary treated water and the primary component in which the phosphorus component is concentrated in the next solid-liquid separation step (2). The primary sludge is then separated into solid and liquid by releasing the phosphorus component mainly as polyphosphoric acid into the liquid phase and solid-liquid separation, so that a small volume of the phosphorus component-rich treated water (secondary treated water) and the phosphorus component Can be separated from the secondary sludge from which water has been removed.

The fourth invention of the present application is directed to the solid-liquid separation step (2).
And a step of concentrating the obtained primary sludge after the step. The volume required for the subsequent phosphorus release step (3) can be reduced by reducing the volume of the sludge in the concentration step. Becomes This leads to a reduction in electric energy required for applying a high-voltage pulse in the process and a reduction in the volume of the processing tank thereafter, so that equipment and maintenance costs can be significantly reduced.

The fifth invention of the present application is characterized in that the concentration step in the fourth invention of the present application is performed by a floating concentration method. The flotation concentration utilizes the fact that sludge floats by adding an air bubble to the sludge to reduce the apparent specific gravity of the sludge. For example, in the case of sedimentation concentration, there is a limit to the concentration rate, and the concentration can be limited to only about 2% of the sludge concentration. Further, depending on the residence time of the sludge, microorganisms are exposed to an anaerobic state, and in the aeration treatment step (1), the internal The accumulated phosphorus component is released again, so that the return water contains phosphorus, and the phosphorus removal rate of the water treatment system may be reduced. Therefore, the sludge can be substantially kept in an aerobic state, sufficient concentration of 4% or more of the sludge concentration can be realized while preventing the re-release of the phosphorus component, and the advantages associated with the above-mentioned sludge concentration can be achieved. Possible flotation enrichment methods are preferably employed in the present invention.

The sixth invention of the present application is directed to the solid-liquid separation step (4).
After the step (2), the method further includes a phosphorus coagulation step (5) of precipitating the released phosphorus component from the liquid phase by adding a coagulant to the secondary treatment water generated in the step. If the component precipitated by this method is recovered, the phosphorus component is obtained as a very concentrated solid component, so that it can be easily used for producing fertilizers and phosphorus compounds, and is advantageous in terms of transportation and handling.

The treatment method of the fifth invention of the present application further includes an anaerobic treatment step (6) before the aeration treatment step (1). By this anaerobic treatment, the anaerobic sludge decomposition and the release of the phosphorus component to the liquid phase are performed prior to the excessive intake of the phosphorus component to the microorganisms, so that the excess intake of the phosphorus component in the aeration treatment is performed more efficiently. Become.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The sludge treatment method of the present invention is characterized in that a sludge is subjected to a high voltage pulse to release phosphorus components in the sludge into a liquid phase. High-voltage pulse is a technology that instantaneously generates a large amount of power by compressing relatively small electric energy over time. To release phosphorus components in sludge using this technology, a sharp It is important to give a short-width pulse with a rising edge. Therefore, in order to generate a high-voltage pulse, first, electric energy is stored, and the electric energy is rapidly released by a high-speed switch. Then, pulse compression, shaping, and pressure increase are performed, and the pulse is supplied to a discharge electrode as a load.

FIG. 2 shows a typical circuit diagram of the high-voltage pulse generator. Capacitor C ₀ that is charged by the introduction of the switch SW is discharged, C ₁ via the inductance L ₀
Sent to At this time, the transmission time τ ₀ of energy from C ₀ to C ₁ is shorter than the charging time T of C ₀ . This circuit is called pulse compression, and a short pulse width required by a plurality of stages of pulse compression can be obtained. The pulse thus compressed is applied to a pulse forming line (P
FL). The output waveform is adjusted by the PFL, the pulse is sharply raised, and a short-time DC high voltage can be applied as a high voltage pulse. If the high-voltage pulse width is shorter than 1 microsecond, the movement speed of various ions in water is lower than that of electrons, so that these ions cannot move between the electrodes. For this reason, when a high-voltage pulse is applied in a gas-liquid mixed state, the applied electric energy is consumed by air discharge and discharge on the droplet surface without being consumed by heat generation or electrolysis, and ozone and radicals are efficiently consumed. It is generated automatically.

The treatment of the sludge by the high voltage pulse is performed by dropping the sludge directly on the discharge electrode as schematically shown in FIG. In FIG. 3, the metal electrode 101 is covered with a dielectric barrier 102 such as glass, which is arranged in a comb shape. The sludge is dropped from above, but even if a high voltage pulse is applied from the high voltage pulse generator 103 to the discharge electrode having such a structure, an arc discharge does not occur and a stable dielectric barrier discharge is caused. Can be. This discharge mainly occurs on the gas-liquid surface, and the cell membrane of microorganisms in the sludge is destroyed by ozone, radicals and shock waves generated at this time, and the phosphorus component contained therein is released as polyphosphoric acid.

In the above high voltage pulse processing, the sludge has a rise time of 300 nanoseconds or less and a pulse width of 1
000 ns or less, peak voltage 10-50 kV, period 1
Voltage may be applied at 0 to 2000 times / second for 10 to 120 minutes. More preferably, the treatment is performed for about 60 nanoseconds with a rise time of about 60 nanoseconds, a pulse width of about 520 nanoseconds, a peak voltage of about 18 kV, and a cycle of 1000 times / second for 60 minutes. If the rise time is too long, there may be a disadvantage that a non-uniform discharge state occurs. If the pulse width is too long, ions may not be able to move between the electrodes as described above. If the peak voltage is too low, no discharge occurs, and if it is too high, the energy efficiency deteriorates. If the cycle is less than the above numerical range, the energy efficiency may deteriorate.

By this treatment, the microorganisms are decomposed by combining the effects of radicals, ozone and shock waves generated by the discharge, and the phosphorus component is mainly released as polyphosphoric acid into the liquid phase. Then, as compared with the case where the phosphorus component is released as orthophosphoric acid or other phosphoric acid derivatives according to the conventional method, a flocculant such as a metal salt necessary for recovering the phosphorus component as a precipitate from the liquid phase is required. The amount is significantly reduced. This is because polyphosphoric acid has a smaller number of free phosphate residues to which a flocculant can bind than the number of phosphorus atoms. In addition, since the metal salt of polyphosphoric acid forms a granular sediment larger than the metal salt of phosphoric acid, in the subsequent recovery treatment, for example, the time required for precipitation separation or centrifugation is reduced,
This is advantageous because the volume can be reduced and the number of revolutions in centrifugation can be reduced.

After performing the treatment for releasing phosphorus, the sludge after the treatment is separated into solid and liquid by ordinary means such as sedimentation, filtration (including membrane separation), and centrifugation, and contains the released phosphorus component. Add a coagulant such as polyaluminum chloride, aluminum sulfate, ferric chloride, ferrous sulfate, calcium chloride, calcium oxide, calcium hydroxide, magnesium chloride, magnesium sulfate, magnesium oxide, magnesium hydroxide, etc. to the liquid phase To precipitate the phosphorus component.
In order to cause precipitation from the phosphorus release treatment solution according to the above method, it is sufficient to add not more than half of the required amount of the flocculant in the same step as in the conventional method. It can be said that the production amount of the compound can be suppressed, which is preferable from the viewpoint of environmental conservation. After the precipitation, the obtained solid component is recovered by a conventional method, subjected to a purification treatment if necessary, and provided as a fertilizer, a phosphorus compound, and other raw materials for producing various drugs.

Hereinafter, an embodiment of the method for treating organic wastewater of the present invention will be described with reference to the schematic flow of FIG.

That is, in the method shown in FIG.
Is first applied to the anaerobic treatment tank 6 to cause anaerobic digestion and release the phosphorus component stored as polyphosphoric acid granules in the microorganism. At this time, the phosphorus component is generally hydrolyzed and released as orthophosphoric acid into the liquid phase. Next, this treatment liquid is applied to an aeration treatment tank 1 provided with an aeration means 11 of an air pump, where decomposition of organic substances by aerobic microorganisms and ingestion of phosphorus components by the microorganisms (storage in the body) are performed. The phosphorus component released in the anaerobic treatment is concentrated in the microorganisms in this step. Thereafter, the aerated liquid is applied to the solid-liquid separating means 2 to separate the primary sludge x in which the phosphorus component is concentrated and the primary treated water a. As the solid-liquid separation means 2, conventionally known filtration including precipitation and membrane separation can be appropriately employed.

In order to release the phosphorus component from the microorganisms contained in the primary sludge x thus obtained into the liquid phase, a high-voltage pulse is applied in the next phosphorus release tank 3 under the above-described conditions, and the phosphorus component is mainly removed. Released from microorganisms as polyphosphoric acid. Then, the required amount of the coagulant B such as a metal salt required for the treatment in the phosphorus coagulation tank 5 for recovering the phosphorus component as a precipitate from the liquid phase is increased by the anaerobic treatment, the ozone treatment, and the alkali treatment as described above. It is significantly reduced as compared with the case where it is released as phosphoric acid. Since the metal salt of polyphosphoric acid forms a large granular sediment, the time required for subsequent recovery treatment, for example, sedimentation separation or centrifugation, the volume, the number of revolutions, and the like can be advantageously reduced.

After the completion of the treatment in the phosphorus release tank 3,
The solid-liquid separation means 4 separates the treated water (secondary treated water) b and the secondary sludge z, each having a relatively small volume, with a high phosphorus content. As the solid-liquid separation means, for example, centrifugal separation, separation by a dehydrator and the like are suitable. Since the volume of the secondary treated water b is much smaller than that of treated water containing a phosphorus component, which is generated by a conventional wastewater treatment method, a phosphorus coagulation process for recovering the phosphorus component as described below is performed. Equipment for
Very small ones will suffice.

In the phosphorus coagulation step, a conventionally known method such as crystallization dephosphorization can be used, but generally, the secondary treatment water b is introduced into the phosphorus coagulation tank 5 and the coagulant B
Is added under stirring to coagulate the phosphorus component as a solid component. Here, since the phosphorus component contained in the secondary treatment water b is mainly obtained as polyphosphoric acid, it can be aggregated into a granular solid component that can be easily recovered even if a small amount of the coagulant B is used. . After adding the flocculant B, stirring and precipitating, the phosphorus component is recovered according to the following steps. Coagulant B
It is most preferable to determine the number of free phosphoric acid residues from the total amount of phosphorus components and polyphosphoric acid contained in the secondary treatment water b, and use only the amount of the number of moles that is sufficient. In addition, in order to improve the recovery rate of the phosphorus component as a solid component during the coagulation reaction in the phosphorus coagulation tank 5, the secondary treatment water b is prepared by adding an appropriate amount of a basic substance such as an aqueous sodium hydroxide solution. pH 8 or more, preferably 8.0-1
The basicity may be adjusted to 0.5, more preferably 9 to 10 basicity.

Next, the tertiary treated water c substantially free of the phosphorus component and the solid phosphorus component y are obtained by the solid-liquid separation means 7. This solid phosphorus component y is separated from the sludge, contains almost no other components contained in the raw wastewater, and is reduced in volume, and contains fertilizers, synthetic detergents, detergents, and metals. It is easy to use as a raw material for ion sequestering agents and food additives, as a raw material for reagents used in papermaking, dyeing, photographic technology, etc., and a raw material for producing phosphorus compounds. However, it is preferable that the phosphorus component p be recovered as a substantially dry solid by the additional phosphorus recovery means 8 so as to be in a form that is most easily distributed and transported. For example, freeze-drying, dehydration,
Drying and the like can be mentioned.

Further, the phosphorus component is converted to phosphate ions and polyphosphate ions or to phosphate salts by using ion exchange chromatography or the like either before or after the treatment step in the phosphorus coagulation tank 5. Separation into a polyphosphate, ie, a phosphoric acid component and a polyphosphoric acid component, may be a supply form of both components that are considered to be used for different purposes.

In the present invention exemplified above, the respective structures of the aeration treatment tank 1, the solid-liquid separation means 7, and the anaerobic treatment tank 6 and the paths connecting these are not particularly limited, and are essentially used conventionally. What has been done can be used. For the device of the present invention, the aeration tank 1 is provided with a diffuser 12 capable of distributing the air sent from the aeration means 11 such as an air pump or a blower into the aeration tank 1 and the anaerobic tank 6 is provided with Preferably, any device provided with a stirring means or the like may be used. Also, the conditions and the like in these steps may be performed according to conventionally known aerobic treatment methods, solid-liquid separation methods, and the like (Japanese Patent Application Laid-Open No.
-10791 and the like).

In brief, the processing in the aeration tank 1 is performed at normal temperature. And solid-liquid separation means 2
For example, means such as precipitation and filtration including membrane separation are selected. Of these, sedimentation is preferred because the equipment and maintenance costs are inexpensive and the operation requires little labor. As the solid-liquid separation means 7, for example, means such as precipitation, filtration (including membrane separation), and centrifugation can be selected. Of these, sedimentation or filtration is preferable because no specially expensive equipment or labor is required, and sedimentation in a sedimentation tank is most preferable if separation is easy depending on the properties of the treatment liquid. The processing temperature in the anaerobic processing tank 6 is not particularly limited, and may be preferably performed at normal temperature. Here, it is preferable to provide a stirring means in the anaerobic treatment tank 6 so as to prevent the phosphorus component released around the microorganism from staying and preventing the release of phosphorus.

The thickening means employed when the primary sludge x obtained from the solid-liquid separating means 2 is subjected to a thickening step includes:
Filtration including sedimentation and membrane separation, centrifugation, flotation concentration, etc. can be used.
The required volume reduction of the tank is realized. When this concentration step is carried out by the flotation concentration method, preferably, in a circulation system using circulating water having a volume of about 4 times the sludge volume, the condition that about 2 to 3% of air is dissolved in the circulating water is used. Adopted.

The phosphorus component finally recovered as the phosphorus component p according to the above-described method is not only concentrated but also considerably purified, so that fertilizers, various phosphorus compounds, production of drugs, etc. It is suitable for being reused as the raw material phosphate rock.

[0039]

According to the present invention, the phosphorus component contained in the organic wastewater can be separated and recovered into a small-capacity liquid or solid state in a short time, so that the phosphorus can be easily reused. You. At this time, since the phosphorus component is concentrated as polyphosphoric acid, the amount of the required flocculant is
A much smaller amount is sufficient than previously known methods.

The method of the present invention is advantageous in that it enables low-cost processing, since it requires no reagent or expensive equipment and has a high phosphorus component recovery rate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a method for treating organic wastewater of the present invention.

FIG. 2 is a circuit diagram showing an electric circuit of the high-voltage pulse generator.

FIG. 3 is a schematic view of a discharge electrode portion used for high-voltage pulse processing in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Aeration treatment tank 2, 4, 7 ... Solid-liquid separation means 3 ... Phosphorus release tank 5 ... Phosphorus coagulation tank 6 ... Anaerobic treatment tank 8 ... Phosphorus recovery means 9 ... Heating means 11 ... Aeration means 12 ... Aeration means 101 ... Metal electrode 102: Dielectric barrier 103: High-voltage pulse generator A: Raw waste water B: Coagulant a: Primary treated water b: Secondary treated water c: Tertiary treated water x: Primary sludge y: Solid phosphorus component z: Secondary Next sludge p ... phosphorus component

Continued on the front page F-term (reference) 4D038 AA08 AB45 AB46 AB47 AB48 BB04 BB10 BB13 BB17 BB18 BB19 4D040 BB07 BB25 BB33 BB65 4D059 AA02 AA03 AA08 BE31 BE37 BE41 BE42 BE49 BH05 BH08 BK30 DA17 DA04 DA05 DA05 DA04 DA05 DA05 DA05 DA16 DA07 DA10 DB01 DB03 DB18 DC13 EA13 EB26 FA04 FA09 FA11 FA13 FA14 FA15

Claims (7)

[Claims] 1. A method for treating sludge, comprising applying a high-voltage pulse to sludge to release phosphorus components in the sludge into a liquid phase. 2. The method according to claim 2, further comprising a step of solid-liquid separating the treatment liquid after performing the phosphorus release treatment, and adding a flocculant to a liquid phase containing the released phosphorus component to precipitate the phosphorus component. Item 7. A method for treating sludge according to Item 1. 3. A method for treating organic wastewater, comprising the following steps: (1) aeration treatment step in which wastewater is subjected to aerobic treatment; and (2) wastewater after aeration treatment is treated as primary treated water and primary treated water. A solid-liquid separation step separated into sludge, (3) a phosphorus release step of applying a high-voltage pulse to release a phosphorus component from the separated primary sludge into a liquid phase, and (4) containing the released phosphorus component A method for treating organic wastewater, comprising a solid-liquid separation step of separating into secondary treated water to be treated and secondary sludge from which phosphorus components have been removed. 4. The treatment method according to claim 3, further comprising a concentration step of concentrating the separated primary sludge after the solid-liquid separation step (2). 5. The processing method according to claim 4, wherein the concentration step is performed by a flotation concentration method. 6. A phosphorus coagulation step (4) in which, after the solid-liquid separation step (4), the released phosphorus component is precipitated from the liquid phase by adding a coagulant to the secondary treatment water generated in the step. The processing method according to any one of claims 3 to 5, further comprising (5). 7. The treatment method according to claim 3, further comprising an anaerobic treatment step (6) before the aeration treatment step (1).