JPH10286591A - Waste disposal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat organic waste water and organic waste easily and efficiently by effectively utilizing methane gas obtained by methane fermentation. SOLUTION: Night soil, waste water, from which residue has been removed, is caused to flow in by a biological treatment means 4 and waste water, from which residue has been removed, of a purification tank is caused to flow into a urine residue separation means 3. Raw liquid, which is solid-liquid separated by means of a solid-liquid separation means 3, is caused to flow into a biological treatment means 4 so as to be subjected to a biological digestion denitrification treatment together with night soil waste water, and excess sludge is removed from the liquid, which liquid is returned to the means 3 and inorganic flocculant is added to separated water to remove aggregated sludge, so that treated water is obtained. Solid waste is crushed and mixed with solids from the means 3 to perform a methane fermentation treatment, following which fermented material and aggregated sludge are agitated and mixed at pH 5-5.5, whereby aggregation is effected again by the aggregating action of remaining aggregated sludge. After solid-liquid separation by a second solid-liquid separation means 16, separated liquid is returned to the means 4 and separated solids are treated separately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste treatment method for treating liquid organic wastewater and solid organic waste capable of utilizing energy generated during methane fermentation treatment.

[0002]

2. Description of the Related Art Conventionally, biological nitrification and denitrification treatment of liquid organic wastewater such as human wastewater such as human waste and septic tank sludge, livestock manure, agricultural and marine products and food processing wastewater, and solid-liquid separated sludge is performed. Methane gas produced by anaerobic methane fermentation treatment with solid waste containing organic waste such as garbage and kitchen garbage and liquid nitrate denitrification treatment with organic wastewater, and methane fermentation treatment BACKGROUND ART There is known a waste treatment method in which methane fermentation is advanced by using waste heat as a process energy while using it for power generation or the like, and liquid organic wastewater and waste are comprehensively treated.

[0003] By the way, solid waste such as garbage is mainly composed of carbohydrates which are easily decomposed by methane fermentation, and has a carbon / nitrogen ratio of 30 and an optimum ratio of methane fermentation treatment of 20. Low nitrogen content. On the other hand, sludge after biological nitrification and denitrification treatment of liquid organic sewage such as human waste sewage has a high carbon / nitrogen ratio of 5 and a large amount of nitrogen and a large amount of proteins and fats. Methane fermentation cannot be digested well. Therefore, the above-mentioned conventional waste treatment method combines the sludge after the biological nitrification and denitrification treatment with the solid waste before the methane fermentation treatment to obtain carbohydrates, proteins and fats at a good carbon / nitrogen ratio. The efficiency of the methane fermentation process is being improved with a good ratio of minutes.

[0004]

However, liquid organic wastewater such as human wastewater generally contains a large amount of nitrogen compounds and phosphorus compounds, and also contains a large amount of organic substances caused by COD and BOD. According to the waste treatment method, the separated water obtained by separating the sludge after the biological nitrification and denitrification treatment cannot be treated by the biological nitrification and denitrification treatment,
Since contaminants such as hardly decomposable organic substances and phosphorus compounds remaining due to the residual nitrogen, advanced treatment such as coagulation using a coagulant, membrane separation, or adsorption using activated carbon, It is necessary to remove organic substances caused by compounds, phosphorus compounds, COD and BOD.

[0005] In the case of membrane separation or adsorption treatment with activated carbon, since there are many contaminants remaining, the treatment load increases, and maintenance and management of the activated carbon and the membrane become complicated.

[0006] In addition, ferric chloride as a coagulant generally used for coagulation of phosphorus compounds together with hardly decomposable and soluble organic matter caused by COD causes coagulation after biological nitrification and denitrification to solidify. When liquid separation is performed and sludge is subjected to methane fermentation treatment with waste, the coagulated iron phosphate in the sludge is reduced and eluted again during the anaerobic methane fermentation treatment, and biological nitrification and denitrification again occurs. It will be returned to the biological treatment tank to be treated, and phosphate ions will be gradually concentrated in the system,
As a result, there is a problem that the treatment cannot be completed with ferric chloride.

[0007] In view of the above problems, an object of the present invention is to provide a waste disposal method capable of efficiently and easily treating organic wastewater and organic waste.

[0008]

According to a first aspect of the present invention, there is provided a waste treatment method comprising the steps of solid-liquid separation of a fermentation product obtained by subjecting a biodegradable solid organic waste to methane fermentation. In a waste treatment method for treating a liquid with a liquid organic wastewater and biological nitrification and denitrification treatment, an inorganic coagulant is added after the biological nitrification and denitrification treatment to separate solid-liquid into coagulated sludge and treated water,
The coagulated sludge is mixed with the fermented product and then subjected to solid-liquid separation. After the biological nitrification and denitrification treatment of the liquid organic wastewater, an inorganic coagulant is added to the solid wastewater to separate it into coagulated sludge and treated water, and the coagulated sludge is a biodegradable solid organic waste. Is mixed with a fermentation product obtained by methane fermentation to separate it into solid and liquid, and the separated liquid is subjected to biological nitrification and denitrification treatment with liquid organic wastewater. Therefore, the untreated pollutants are coagulated and separated in the methane fermentation treatment, so that they are highly efficiently treated.

According to a second aspect of the present invention, in the waste disposal method of the first aspect, after the biological nitrification and denitrification treatment, solid-liquid separation into excess sludge and separated water is performed, and the excess sludge is organically separated. A methane fermentation treatment is performed with a municipal waste, and an inorganic coagulant is added to the separated water to perform solid-liquid separation into coagulated sludge and treated water. After the biological nitrification and denitrification treatment of the liquid organic wastewater, it is solid-liquid separated into excess sludge and separated water, the excess sludge is subjected to methane fermentation with organic waste, and an inorganic coagulant is added to the separated water. And solid-liquid separation into coagulated sludge and treated water.The coagulated sludge is mixed with a fermentation product obtained by subjecting a biodegradable solid organic waste to methane fermentation, followed by solid-liquid separation. Since the liquid is subjected to biological nitrification and denitrification treatment with liquid organic sewage, the ratio of carbon / nitrogen during methane fermentation becomes a good ratio by mixing surplus sludge and organic waste, and methane fermentation is performed efficiently. And organic wastewater and organic waste are highly efficiently treated.

[0010] According to a third aspect of the present invention, in the waste disposal method of the first or second aspect, the pH is controlled to be acidic when the coagulated sludge is mixed with the fermentation product. Then, in order to control the pH to be acidic during the mixing of the fermentation treatment product and the coagulated sludge after the methane fermentation treatment, the remaining coagulation action of the coagulation sludge acts efficiently and remains without being treated in the methane fermentation treatment. Contaminants are efficiently aggregated.

According to a fourth aspect of the present invention, there is provided a waste disposal method according to any one of the first to third aspects.
When the coagulated sludge is mixed with the fermentation treatment product, an inorganic coagulant is added. In addition, when mixing the coagulated sludge and the fermentation treatment product, since an inorganic coagulant is added separately, the contaminants remaining without being treated in the methane fermentation treatment are highly coagulated, and highly organic wastewater and organic Waste is disposed of.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a waste disposal method according to the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes first sewage removing means. The first sewage removing means 1 is constituted by combining, for example, a screen or a screw press having a mesh width of about 1 mm in multiple stages. In addition, foreign substances mixed into human waste as organic wastewater are removed. Reference numeral 2 denotes a second sewage removing means. The second sewage removing means 2 is configured in the same manner as the first sewage removing means 1, and the sewage mixed into the septic tank sludge as organic sewage. Remove residue and contaminants. The removed sewage and contaminants are formed into pellets, converted into solid fuel, processed into building materials, or incinerated.

[0014] A waste separation means 3 is connected to the second waste removal means 2. This waste separation means 3
The septic tank sewage from which the sewage and contaminants have been removed from the septic tank sludge by the second sewage removing means 2 can flow in.

The first waste removing means 1 is connected to a biological treatment means 4 for biologically purifying waste human sewage from which foreign substances have been removed by a biological digestion and denitrification reaction. The biological treatment means 4 may be configured to generate a nitrification denitrification reaction in one tank, or may be constituted by two tanks of a denitrification treatment tank and a nitrification treatment tank. A configuration in which a tank for aerobic microorganism treatment with microorganisms is added may be employed.

The biological treatment means 4 is connected to a sludge separation means 5 for solid-liquid separation of excess sludge from the biological treatment liquid after the biological nitrification and denitrification treatment. The sludge separating means 5 separates the excess sludge by filtration separation, sedimentation separation processing, centrifugal separation processing and the like of the biological treatment liquid by a screen or a membrane, returns the sludge to the waste separation means 3, and is combined with the septic tank sewage. . Then, in the sewage separation means 3, the sludge and the undiluted solution are separated together with the sewage and impurities remaining without being separated and removed by the second sewage removal means 2, and the undiluted solution is sent to the biological treatment means 3. The undiluted solution is subjected to biological digestion and denitrification together with the human wastewater from which the contaminants have been removed by the biological treatment means 3.

The sludge separating means 5 is connected with a flocculating means 6 for adding an inorganic flocculant such as ferric chloride to the separated water separated by the sludge separating means 5 to perform a flocculating treatment. I have.

Further, the aggregating means 6 includes
The first solid-liquid separation means 7 is connected to separate the coagulation treatment liquid, which has been subjected to coagulation processing, into coagulation sludge and treated water by filtration separation, sedimentation separation processing, centrifugation, or the like using a screen or membrane. The treated water is discharged out of the system, for example, by being discharged.

On the other hand, reference numeral 11 denotes garbage pre-processing means. The garbage pre-processing means 11 crushes waste including biodegradable organic waste such as garbage and agricultural and marine wastes. It comprises a crushing device for crushing, and a metal removing device for magnetically sorting while washing the crushed material in which waste is crushed by the crushing device.

The refuse pretreatment means 11 includes a preparation means 12
Is connected. The preparation means 12 is connected to a waste transfer means 13 for transferring the waste, impurities, and excess sludge separated by the waste separation means 3 and putting the sludge into the preparation means 12. Then, the preparation means 12, the sewage contaminated by the sewage conveyance means 13, contaminants and excess sludge and the crushed waste from the pretreatment means, while adding water, appropriately, for example, about The mixture is heated to 55 ° C. and stirred and mixed to prepare a refined product.
Note that steam is preferably used for adding water and heating. By using steam, there is no need to add water and heat it separately with a heating means.
Stirring can be performed.

The preparation means 12 is connected to a methane fermentation means 14 for performing methane fermentation treatment on the prepared refined material. The methane fermentation means 14 performs methane fermentation treatment of organic substances with methane bacteria or the like while appropriately heating and stirring at 55 ° C. The methane fermentation means 14 is provided with a methane gas recovery means (not shown) for recovering generated methane gas. The recovered methane gas is used for power generation and the like, and is used as operating energy in the treatment of human wastewater and organic wastewater.

The methane fermentation means 14 is connected to a mixing means 15 for stirring and mixing the fermentation product obtained by the methane fermentation treatment and the coagulated sludge separated by the first solid-liquid separation means 7. ing. The mixing means 15 includes a pH control means (not shown) for measuring the pH of the mixture of the fermentation treatment product and the coagulated sludge and controlling the pH to an acidic atmosphere, preferably a pH of 5 to 5.5, and an inorganic atmosphere such as ferric chloride. And a coagulant adding means for adding a coagulant.

The mixing means 15 further comprises a second solid-liquid separator for subjecting the stirred and mixed mixture to solid-liquid separation by various solid-liquid separation methods such as filtration, sedimentation, and centrifugation using a screen or a membrane. Separation means 16 is connected. Then, the separated liquid separated by the second solid-liquid separating means 16 is returned to the biological treatment means 4 by the separated liquid returning means 17,
The solid content is formed into pellets, converted to solid fuel, processed into building materials, or incinerated. The separated liquid returning means 17
May be returned to the waste separation means 3.

Next, the operation of the above embodiment will be described.

First, the human waste is allowed to flow into the first waste removing means 1 to be separated into solid waste and liquid human waste water, and the human waste water is flown into the biological treatment means 4.

On the other hand, the sludge from the septic tank is removed by the second
To separate the waste into solid waste and liquid wastewater from the septic tank. Then, the undiluted solution separated into solid and liquid by the sewage separation means 3 flows into the biological treatment means 4, and the undiluted solution is subjected to biological nitrification and denitrification together with the sewage wastewater in the biological treatment means 4. Part of the organic substances, nitrogen compounds and phosphorus compounds contributing to the BOD to be mixed are treated.

Thereafter, the biological treatment liquid after the biological nitrification and denitrification treatment is allowed to flow into the sludge separating means 5, where it is separated into excess sludge and separated water by filtration or sedimentation treatment using a screen or membrane. I do. Then, the excess sludge is returned to the waste separation means 3, and the separated water flows into the flocculation means 6.

Next, the separated water flowing into the flocculation means 6 is
For example, an inorganic coagulant such as ferric chloride is added, and coagulation treatment is performed on organic substances and phosphorus compounds that contribute to COD in addition to organic substances and nitrogen compounds that contribute to BOD remaining in the separated water. Thereafter, the flocculated liquid subjected to the flocculation treatment flows into the first solid-liquid separation means 7 and is separated into flocculated sludge and treated water by various solid-liquid separation methods such as filtration or sedimentation separation using a screen or membrane. Separate the liquid. Then, the treated water is discharged out of the system.

On the other hand, solid wastes including biodegradable organic wastes such as garbage, agricultural and marine wastes, and sludge are put into a crushing device of the garbage pretreatment means 11 and crushed. The metal is removed by magnetic sorting while washing the crushed material with a metal removing device.

Then, the crushed waste of the crushed waste after the magnetic separation is charged into the preparation means 12 and the waste transport means
The waste, impurities, and excess sludge separated by the waste separation means 3 through 13 are introduced. Thereafter, while heating to about 55 ° C. using, for example, steam, the crushed waste and the waste, impurities, and sludge are stirred and mixed to prepare a refined material. By stirring and mixing the crushed waste material with the sewage, impurities and sludge, the organic substances and the like adhering to the sewage, impurities and sludge are reduced in viscosity and are solubilized in warm water generated by condensation of steam. . Thereafter, the refined product prepared by stirring and mixing for a predetermined time is allowed to flow into the methane fermentation means 14, for example, at 55 ° C.
And the organic substance is subjected to methane fermentation treatment with methane bacteria or the like. The methane gas generated by the methane fermentation treatment is collected by a methane gas recovery means and used for power generation and the like, and is used as operating energy in the treatment of human wastewater and organic wastewater.

Next, a fermented product obtained by subjecting the refined material to methane fermentation by the methane fermentation means 14 flows into the mixing means 15 and is mixed with the flocculated sludge separated by the first solid-liquid separation means 7 with stirring. At the time of this stirring and mixing, the pH is adjusted to acidic, preferably the pH is adjusted to 5 to 5.5 by the pH control means while adding an inorganic coagulant such as ferric chloride by the coagulant addition means, and coagulation treatment is performed. . In this coagulation treatment, the coagulation sludge supplied from the first solid-liquid separation means 7 retains the coagulation action of the inorganic coagulant added by the coagulation means 6, and is added with the remaining coagulation action. The coagulation treatment is caused by the coagulation action of the inorganic coagulant.

Thereafter, the second solid-liquid separating means 16 separates the separated liquid and the solid into solids and liquids by various solid-liquid separation methods such as filtration separation using a screen or a membrane, sedimentation separation processing, and centrifugal separation processing. I do. Then, the separated liquid is returned to the biological treatment means 4 by the separated liquid returning means 17 to be combined with the human wastewater and the undiluted liquid and subjected to biological treatment, and the solid content is formed into pellets to be converted into solid fuel, building material, etc. RDF processing,
Dispose of by incineration.

By the way, wastes containing organic wastes such as garbage are mainly composed of carbohydrates which are easily decomposed by methane fermentation, but have a carbon / nitrogen ratio of 30 and an optimum ratio of methane fermentation treatment. There is less nitrogen content than some 20. On the other hand, sludge after biological treatment of human wastewater, which is an organic wastewater, has a carbon / nitrogen ratio of 5 and a large amount of nitrogen, and has a large amount of proteins and fats. Therefore, it is subjected to methane fermentation treatment as solid waste. Can not digest well. However, in the above embodiment, a good carbon / nitrogen ratio is obtained by mixing waste such as garbage and excess sludge, and the ratio of carbohydrate, protein and fat is also good, and methane fermentation treatment is performed. Can proceed efficiently.

As described above, the above embodiment is different from the first embodiment.
The sewage and septic tank sewage from which sewage and contaminants have been separated by the sewage removal means 1 and the second sewage removal means 2 are subjected to biological nitrification and denitrification treatment by the biological treatment means 4 to obtain sludge separation means. The excess sludge is separated at 5 and further subjected to a coagulation treatment using an inorganic coagulant at a coagulation means 6 to be solid-liquid separated into coagulated sludge and treated water by a first solid-liquid separation means 7 and separated. The sewage, contaminants and surplus sludge and the waste containing biodegradable organic waste are subjected to methane fermentation treatment by the methane fermentation means 14, and the treated fermentation product is first mixed by the mixing means 15.
Is mixed with the coagulated sludge solid-liquid separated by the solid-liquid separation means 7, and subjected to coagulation treatment again using the remaining coagulation action of the coagulated sludge.
The solid-liquid separation is performed by the second solid-liquid separation means 16, and the separated liquid is returned to the biological treatment means 4.

[0035] For this reason, the organic waste adhering to the sewage, impurities and sludge separated from the human wastewater is digested together with the organic waste by the methane fermentation treatment, and the sewage is discharged out of the system with the organic matter attached. The methane fermentation treatment can be performed efficiently without being performed, and the treatment cost can be reduced by effectively utilizing the methane gas generated by the methane fermentation.

Further, utilizing the remaining coagulation action of the inorganic coagulant added after the treatment of human wastewater, phosphorus compounds such as phosphate ions untreated in methane fermentation treatment, hardly decomposable organic substances caused by COD, etc. The agglutination separation of the contaminants of the present invention enables highly efficient treatment of human wastewater and waste.

Further, since the separated liquid subjected to solid-liquid separation by the second solid-liquid separating means 16 is returned to the biological treatment means 4 by the separated liquid returning means 17, the organic matter in the untreated separated liquid by methane fermentation is returned. Pollutants such as calcium ions, phosphate ions, and ammonium ions can be highly purified by biological treatment and subsequent coagulation treatment using the energy obtained from methane fermentation, and can efficiently and efficiently remove human wastewater and waste. Can be processed.

Further, before the treated liquid subjected to the biological treatment is subjected to the coagulation treatment by the coagulation means 6, the excess sludge is separated by the sludge separation means 5 and returned to the waste separation means 3, and the separated water is collected by the coagulation means 6. , The inorganic flocculant can act only on the contaminants that remain after being dissolved and cannot be treated by the biological treatment, and the amount of the inorganic flocculant can be reduced. Methane fermentation treatment by being mixed with organic waste through the methane fermentation treatment, the carbon / nitrogen ratio of the methane fermentation treatment becomes a good ratio, the methane fermentation treatment can proceed efficiently, and highly efficient sewage wastewater and Can process waste.

Further, when treating waste, methane fermentation treatment is not performed directly, but crushed in advance by the garbage pretreatment means 11 and then mixed by the preparation means 12 for methane fermentation treatment. Even if contaminants difficult to biodegrade are mixed in, the contaminants are crushed together with the organic waste to have a substantially uniform composition, solubilizing contaminants such as organic substances and methane during subsequent mixing. The fermentation process can proceed efficiently.

In the above embodiment, the preparation means
Before the mixture prepared in 12 is subjected to methane fermentation treatment by the methane fermentation means 14, impurities such as synthetic resin films, plastics, styrene foam, and glass, which are extremely difficult to biodegrade, may be separated and removed while washing. The removed contaminants are, for example, separately formed into pellets, subjected to RDF processing into solid fuel or building materials, or incinerated. According to this configuration, during the methane fermentation treatment, substances that cannot be digested by living organisms are not mixed, and the methane fermentation treatment can be performed efficiently.

Further, the human waste and the septic tank sludge are separated from each other by the first
The above description has been made by removing sewage and contaminants by the sewage removal means 1 and the second sewage removal means 2, respectively. However, the sewage is an organic sewage in which sewage, septic tank sludge, and liquid waste are mixed in advance. In the case of system wastewater, after separating the sewage, the sewage separation means 3 performs treatment by various solid-liquid separation methods such as filtration separation by a membrane or the like, sedimentation separation processing, centrifugal separation treatment, coagulation separation treatment and the like. Thereafter, the liquid component may be subjected to biological treatment, and the solid component may be introduced into the preparation means 12 for treatment. Further, the human waste sewage may be directly separated into solid and liquid by the waste separation means 3 without separating the waste. According to these configurations, the configuration can be simplified and the size of the device can be reduced.

Further, although the description has been made with the addition of the inorganic flocculant in the mixing means 15, it is also possible to simply mix the flocculated sludge and the fermentation product by stirring. In addition, since the inorganic flocculant is added by the mixing means 15, the treatment can be further advanced.

In the above description, the separated liquid separated by the second solid-liquid separating means 16 is returned to the biological treatment means 4 by the separated liquid returning means 17, but the separated liquid is separated separately from the human wastewater. May be processed.

Although the preparation means 12 is provided and mixed before the methane fermentation treatment, the methane fermentation means 14 is directly mixed with the waste and contaminants from the waste separation means 3 and the waste from the pretreatment means 11. A thing may be thrown in and processed.

In the above description, the waste and the contaminants are mixed with the waste while being heated by the preparation means 12, but it is also possible to simply mix without heating.

[0046]

EXAMPLE A garbage slurry with a moisture content of 81% obtained by mixing and grinding 0.15 kg of excess sludge with a moisture content of 82% generated by nitrification and denitrification treatment in a human waste treatment plant and vegetables, fruits, meat, fish, cooked rice and the like. 1.2 kg were mixed and diluted with 1.32 kg of water to prepare a mixture having a TS concentration of about 10%. In addition, the excess sludge and the coagulated sludge were set to be 8: 2 as a dry matter weight ratio.

Then, the mixture was placed in an acrylic methane fermentation tank having a digestion period of 50 days and a real volume of 5 liters.
C. for 10 days, and methane fermentation was continuously processed by a gas stirring method. Table 1 shows the water quality of the fermented product after 30 days.

[0048]

[Table 1] Further, 1 kg of the fermentation treatment product having the properties shown in Table 1 was coagulated and separated with ferric chloride into separated water from which excess sludge was separated after nitrification and denitrification treatment in a human waste treatment plant, and the water content was 78%. 0.01 kg of coagulated sludge was mixed well with stirring, and then separated into solid and liquid by centrifugation to measure the water quality of the supernatant. Table 2 shows the results.

[0049]

[Table 2] From the results shown in Tables 1 and 2, it is understood that the flocculation sludge that has been flocculated by the flocculation means 7 has a sufficient flocculating action and can be further flocculated.

On the other hand, when mixing the fermented product and the flocculated sludge, the pH was appropriately varied with hydrochloric acid, the supernatant was collected by centrifugation, and the water quality was measured. Table 3 shows the results.
And FIG.

[0051]

[Table 3] From the results shown in Table 3 and FIG.
It can be seen that the phosphate atmosphere was reduced by controlling the acidic atmosphere of No. 5, that is, the phosphate ions were aggregated by the aggregation action of the aggregated sludge.

[0052]

According to the waste treatment method of the present invention, an inorganic coagulant is added to a liquid organic wastewater after biological nitrification and denitrification treatment to separate the liquid waste into a solid-liquid separation into coagulated sludge and treated water. This coagulated sludge is mixed with a fermentation product obtained by subjecting a solid organic waste that can be biodegraded to methane fermentation to solid-liquid separation, and the separated liquid is mixed with liquid organic wastewater and biological nitrification. Since the denitrification treatment is performed, the untreated contaminants are coagulated and separated in the methane fermentation treatment utilizing the remaining coagulation action of the coagulated sludge, so that the treatment can be performed with high efficiency.

According to the waste disposal method of the second aspect,
In addition to the effect of the waste treatment method according to claim 1, the liquid organic sewage is subjected to biological nitrification and denitrification treatment and then solid-liquid separated into excess sludge and separated water. Treatment, adding an inorganic coagulant to the separated water, solid-liquid separation into coagulated sludge and treated water, and fermentation obtained by subjecting this coagulated sludge to biodegradable solid organic waste by methane fermentation. It is mixed with the treated material to separate it into solid and liquid, and the separated liquid is subjected to biological nitrification and denitrification treatment by liquid organic sewage. By mixing excess sludge and organic waste, carbon / nitrogen in the methane fermentation treatment is mixed. The ratio becomes a good ratio, the methane fermentation treatment can proceed efficiently, and organic wastewater and organic waste can be treated highly efficiently.

According to the waste disposal method of the third aspect,
In addition to the effect of the waste treatment method according to claim 1 or 2, since the pH is controlled to be acidic when the fermentation treatment product after the methane fermentation treatment is mixed with the coagulation sludge, the remaining coagulation action of the coagulation sludge is reduced. It works efficiently and can efficiently condense the contaminants remaining without being treated in the methane fermentation treatment.

According to the waste treatment method of the fourth aspect,
In addition to the effect of the waste treatment method according to any one of claims 1 to 3, when the coagulated sludge and the fermented product are mixed, an inorganic coagulant is added separately, so that the mixture remains without being treated by the methane fermentation treatment. It is capable of highly coagulating pollutants and highly treating organic wastewater and organic waste.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a waste disposal method according to the present invention.

FIG. 2 is a graph showing the concentration of phosphate ions due to the addition of ferric chloride at each pH.

[Explanation of symbols]

 Reference Signs List 4 biological treatment means 5 sludge separation means 6 flocculation means 7 first solid-liquid separation means 14 methane fermentation means 15 mixing means 16 second solid-liquid separation means 17 separated liquid return means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Sasaki 2-1-1-9, Nobori, Nishi-ku, Osaka-shi, Osaka Inside Ataka Industry Co., Ltd.

Claims (4)

[Claims] 1. A fermentation treatment product obtained by subjecting a biodegradable solid organic waste to a methane fermentation treatment to perform solid-liquid separation, and separating the separated liquid into a liquid organic wastewater and a biological nitrification denitrification treatment. In the waste treatment method, after the biological nitrification and denitrification treatment, an inorganic coagulant is added to perform solid-liquid separation into coagulated sludge and treated water, and the coagulated sludge is mixed with the fermentation treatment product and then solid-liquid. A waste disposal method characterized by separating. 2. After the biological nitrification and denitrification treatment, solid-liquid separation into excess sludge and separated water is performed, the excess sludge is subjected to methane fermentation treatment with organic waste, and an inorganic coagulant is added to the separated water. The waste treatment method according to claim 1, wherein solid-liquid separation is performed into coagulated sludge and treated water. 3. The waste treatment method according to claim 1, wherein the pH is controlled to be acidic when the coagulated sludge is mixed with the fermentation treatment product. 4. The waste treatment method according to claim 1, wherein an inorganic coagulant is added when the coagulated sludge is mixed with the fermented product.