JP2000015229A - Method for treating organic waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating organic waste which can separate fermentation unsuitable substances such as phosphorus and fish bones and attempt the effective use and efficient treatment of separated phosphorus. SOLUTION: A mixture 9 of crushed garbage 7, excrement, sewage purifier sludge, and others is led to a two-liquid flocculating/dewatering process and, after phosphorus contained in the mixture 9 being flocculated, separated into solids 12 containing flocculated phosphorus and separated liquid 13. The separated solids 12 are led to a composting process, fermented under aerobic conditions. and recovered as compost 14. The separated liquid 13 is led to an anaerobic fermentation process and fermented under anaerobic conditions, and biogas 15 such as generated methane is recovered. In this way, good compost 14 containing enough amounts of nitrogen and phosphorus effective as fertilizer components can be obtained. A phosphorus-removing operation is unnecessary for dewatered filtrate 18 separated from digested sludge 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating organic wastes in which a plurality of types of organic wastes having different properties and concentrations are treated in the same treatment system and useful substances are recovered.

[0002]

2. Description of the Related Art Conventionally, organic waste has been recycled. For example, Japanese Patent Application Laid-Open No. Hei 9-201699 discloses that human waste, septic tank sludge, sewage sludge, agricultural sludge, livestock manure, garbage and foods are disclosed. Organic waste with different properties and concentrations, such as waste, is treated in the same system to collect useful substances,
A method for recycling is disclosed.

This method is as shown in FIG. 3. In this method, human waste, septic tank sludge, agricultural sludge, sewage sludge, and livestock manure are removed in a removing step # 31, and a solid-liquid separation step # 3 is performed.
In 2, the liquid waste 31 and the dewatered sludge 32 are separated,
The liquid waste 31 is subjected to BOD decomposition and denitrification as necessary in the biological treatment step # 33, and suspended matter is removed in the solid-liquid separation step # 34. COD, pigment components, iron and manganese are removed in the advanced treatment step # 35. Heavy metals such as are removed and disinfected for effluent or reused water.

On the other hand, garbage and food waste are crushed in a crushing / separating step # 36, plastic bags and trays are separated, and then mixed with the above-mentioned dewatered sludge 32.
The fermentation is performed in the anaerobic fermentation step # 37, the generated methane gas 33 is collected, and used in the form of electricity or heat in the power generation step # 38 or the like.
Is converted into a dewatered sludge 35 in a dehydration step # 39, sent to a composting step # 40 and the like to be collected as fertilizer, solid fuel and dried sludge, and the dehydrated filtrate 36 is sent to a biological treatment step # 33 for processing.

[0005]

However, the digested sludge 34 generated in the anaerobic fermentation step # 37 as described above.
Since there are few organic components, the amount of heat and the fertilizing component may be insufficient when composting the dewatered sludge 35 obtained by dehydrating it. On the other hand, since phosphorus moves to the dehydrated filtrate 36 side, the phosphorus removal operation must be performed in the biological treatment step # 33 for treating the dehydrated filtrate 36 or other water treatment steps.

In addition, crushed and separated food waste and food waste contain a large amount of small anaerobic fermentation unsuitable substances such as fish bones, and there is a problem that they accumulate in the fermenter.

The present invention solves the above-mentioned problems, and can efficiently separate anaerobic fermentation unsuitable substances such as phosphorus and fish bones, and can effectively use the separated phosphorus and improve the efficiency of the treatment. It is an object of the present invention to provide a method for treating waste.

[0008]

In order to solve the above problems, a method for treating organic waste according to claim 1 of the present invention is a method for treating a plurality of types of organic waste having different properties and concentrations in the same treatment system. At the time of collecting useful substances, crushing solid organic waste such as garbage into the crushing process,
As a mixture of the crushed material and human waste, sludge-like organic waste such as septic tank sludge, at least one of them is led to a two-part coagulation dehydration step in which two types of coagulants having a phosphorus coagulation effect are added, and into the mixture. The contained phosphorus is aggregated, separated into a solid containing aggregated phosphorus and a desorbent, and the separated phosphorus-containing solid is led to a composting step, fermented under aerobic conditions, and collected as compost In addition, the desorbed liquid is guided to an anaerobic fermentation step, fermented under anaerobic conditions, and biogas such as methane generated is collected.

According to a second aspect of the present invention, in the crushing step, an organic waste is provided by a compression crusher having a fine crushing discharge hole and performing compression crushing by a high pressure applied instantaneously. Crushing.

[0010] The method of treating organic waste according to claim 3 is characterized in that the organic waste having a low biodegradation rate is solubilized and liquefied before the two-liquid coagulation dehydration step. According to the configuration of the above-mentioned claim 1, phosphorus in the mixture is reliably transferred to the solid matter side by performing the two-liquid coagulation dehydration, and the phosphorus-containing solid matter is fermented under aerobic conditions. The organic matter present in the fermentation is efficiently fermented while generating a large amount of heat, and a good compost sufficiently containing nitrogen and phosphorus as fertilizing components can be obtained. In addition, since the desorbed liquid from which phosphorus has been removed is fermented under anaerobic conditions, it is not necessary to remove phosphorus from the dehydrated filtrate desorbed from the generated digested sludge.

According to the second aspect of the present invention, the organic waste which was conventionally difficult to crush is discharged while being finely crushed in the crushing discharge hole by the applied high pressure. Unsuitable materials remain in the apparatus because they cannot enter the crushing discharge hole even by high pressure, and are automatically separated. The finely crushed organic waste is efficiently fermented, and organic components are recovered at a high rate.

According to the third aspect of the present invention, since the organic waste having a low biodegradation rate is liquefied in advance, the liquefied organic waste is subjected to anaerobic fermentation through a two-liquid coagulation and dehydration step. The fermentation can be carried out efficiently in either the process or the composting process.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows the flow of treating organic waste such as night soil, septic tank sludge, sewage sludge, agricultural sludge, livestock manure, garbage, food waste, etc. in the same processing system to collect useful resources and turn them into resources. Is shown.

Night soil, septic tank sludge, sewage sludge, agricultural sludge,
The sludge-like organic waste such as livestock manure is led to the concentration step # 1, and depending on the properties, an organic polymer flocculant 1 is added to perform solid-liquid separation, thereby forming a concentrated sludge 2 and a separated liquid 3. The concentration step # 1 may be performed by granulation concentration, screen concentration, or the like according to a desired sludge moisture content, and can be omitted when unnecessary. A residue removal step may be provided before the concentration step # 1.

The separation liquid 3 is introduced into the biological treatment step # 2,
BOD decomposition and, if necessary, denitrification,
Leads to the subsequent processing not shown. Biological treatment process # 2
The excess sludge 5 generated in the above is appropriately extracted, but because of low biodegradability, it is led to the solubilization step # 3 together with other low biodegradable organic waste, and is subjected to solubilization treatment to liquefy and reduce the molecular weight. Become About 70-
Maintain at 80 ° C. for 3 days; maintain at 70 ° C., high temperature and high pressure of about 0.3 MPa; add alkali such as caustic soda or slaked lime to maintain at about 70 ° C .; blow ozone gas; maintain at 130 to 175 ° C. And various methods. Although the solubilization step # 3 is not necessarily performed, the liquefaction and the reduction of the molecular weight can enhance the biodegradability. The obtained liquefied material 6 is subjected to a concentration step # 1
And then sent to the biological treatment step # 2 for treatment, or if there is no concentration step # 1, treatment as described later.

On the other hand, other organic wastes containing fermentation unsuitable substances such as plastics, such as garbage and food waste, and containing an inhomogeneous solid content, are subjected to a crushing / sorting step # 4. And compression crushing.

The crushing machine used is, for example, a compression crushing machine as shown in FIG. 2, and the crushing object introduced from the inlet 111 and sent out of the chamber 113 by the feeder 112 is uniformly distributed depending on the properties. After adjusting with dilution water so that pressure is applied, hydraulic cylinder 1
200-250 kg / cm that is instantaneously loaded by 14
Compressed at a high pressure of ² , and extruded through a fine crushing discharge hole (not shown) formed in a slit shape to crush into fine particles (paste or flakes depending on the properties of the object to be crushed) The crushed material is discharged through the outlet 115, and the residue is separately taken out from the residue outlet 116.

For this reason, organic wastes such as garbage are discharged as flowable fine particles 7 having a particle size of 1 to 2 mm or less, and are not crushable, such as plastics, metals, stones and sands.
Unsuitable fermentation materials 8 such as fish bones are automatically and simultaneously separated by remaining. The moisture content of the unsuitable fermentation product 8 is low, and the adhesion of organic waste to the unsuitable fermentation product 8 is very small. Depending on the properties of the garbage and the food waste, the coarse crushing step may be provided to increase the amount of the raw material to be introduced into the compression crusher, thereby increasing the processing amount.

Next, the fine particulate matter 7 and the above-mentioned concentrated sludge 2 (in some cases, sludge-like organic waste or liquefied matter 6) are mixed, and the mixture 9 is led to a two-pack coagulation dewatering step # 5. Then, the mixture is introduced into a dehydrator such as a centrifugal dehydrator, a belt press, a filter press, and a screw press, and two kinds of coagulants 10 and 11 are sequentially added to the mixture 9 in the introduction path, mixed, and dehydrated.

At this time, it is essential that one coagulant 10 has a phosphorus coagulation effect, and the other coagulant 11 may or may not have a phosphorus coagulation effect. Examples of the flocculant 10 include an aluminum-based flocculant such as a sulfate band, aluminum chloride, aluminum sulfate, and TK floc;
Iron-based flocculants such as ferrous sulfate, ferric sulfate, and ferric chloride;
Inorganic flocculants such as magnesium chloride and slaked lime, flocculants 11
An organic polymer flocculant such as an amphoteric polymer or a cationic polymer can be suitably used. By adding such two kinds of coagulants 10 and 11, phosphorus contained in the mixture 9 is surely aggregated, the dehydration property of the mixture 9 is improved, and the solid matter 12 containing the aggregated phosphorus is desorbed. It is well separated from the liquid 13.

The separated phosphorus-containing solids 12 are led to a composting step # 6, and fermented under aerobic conditions, and collected as compost 14. At that time, the fine particulate matter 7
As described above, not only are the particles disintegrated by compression crushing, but also the cell membrane is partially destroyed, so the biodegradability is extremely large, and organic waste that has been conventionally excluded as difficult to crush is excluded. The organic waste which has been removed by being attached to the material or the fermentation unsuitable material 8 is also contained in the fine particulate matter 7, and also has food waste, food waste, human waste, septic tank sludge, and the like. There is also the effect of mixing different components, for example, trace elements (Fe, Ni, Co, etc.), and abundant organic matter is efficiently fermented while generating a large amount of heat, and as a fertilizing component Good compost 14 sufficiently containing nitrogen and phosphorus is obtained.

The separated liquid 13 is subjected to an anaerobic fermentation step # 7.
The fermentation is performed in an acid fermentation tank and then in a methane fermentation tank under anaerobic conditions. Since the desorbed liquid 13 containing no solid is used as a raw material, both the acid fermentation and the methane fermentation have high rates. Biogas such as methane generated in a methane fermentation tank 1
5 is recovered, desulfurized, etc., and then used in the same manner as before.

The fermented sludge 16 generated in the methane fermentation tank is
The dehydration step # 8 may be followed by dehydration, collected as a dehydrated cake 17 and made into a solid fuel or the like as in the related art, or may be mixed with the phosphorus-containing solid material 12 to be composted. The desorbed liquid 18 is returned to the biological treatment step # 2 for processing. However, since phosphorus is not contained, a conventional phosphorus removing operation is not required.

The load of the organic substance supplied to the anaerobic fermentation step # 7 can be adjusted by adjusting the dehydration rate in the two-liquid coagulation dehydration step # 5, so that the size of the fermenter can be reduced.

In the anaerobic fermentation step # 7, the fermentation can be further promoted by increasing the concentration of methane bacteria in the fermenter. For example, the UASB method (upflow sludge blanket method) can be used. Use of a membrane separation type fermenter is possible.

[0026]

As described above, according to the present invention, a mixture of a crushed material obtained by crushing garbage and the like, human waste, a septic tank sludge, etc., is led to a two-pack coagulation dewatering step, and the mixture is contained in the mixture. Phosphorus is coagulated, separated into solids containing coagulated phosphorus and a desorbed liquid, and the phosphorus-containing solids are fermented under aerobic conditions, so that abundant organic matter efficiently generates a large amount of heat while generating a large amount of heat. Fermentation results in good compost sufficiently containing nitrogen and phosphorus as fertilizer components, and also reduces the amount of heat supplied from the outside to prepare the fermentation environment. In addition, since the desorbed liquid from which phosphorus has been removed is fermented under anaerobic conditions, no phosphorus removal operation is required for the dehydrated filtrate desorbed from the digested sludge.

In addition, since a compression crusher is used, organic wastes which were conventionally difficult to crush can be finely crushed, fermented efficiently, and organic components can be recovered at a high rate. At the same time, unsuitable fermentation products such as fish bones can be automatically separated at the same time, transferring unsuitable fermentation products to acid fermentation tanks or methane fermentation tanks and preventing accumulation in the tanks. Miniaturization is also possible.

Further, the organic waste having a low biodegradation rate is solubilized and liquefied before the two-liquid coagulation and dehydration step, so that the liquefied organic waste is subjected to two-liquid coagulation and dehydration. Through the process, the fermentation can be performed efficiently in either the anaerobic fermentation process or the composting process.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a method for treating organic waste according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a compression crusher used in the method for treating organic waste shown in FIG.

FIG. 3 is a flowchart showing a conventional organic waste treatment flow.

[Explanation of symbols]

 5 Excess sludge 6 Liquefied matter 7 Crushed material 9 Mixture 10,11 Flocculant 12 Solid matter 13 Desorbed liquid 14 Compost 15 Biogas

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuya Yamamoto 2-47, Shikitsu Higashi 1-chome, Namiwa-ku, Osaka-shi, Osaka (72) Inventor Toshiyuki Shibata Toshiyuki Shibata Higashi-ichi Shikitsu, Naniwa-ku, Osaka, Osaka No. 2-47 F-term in Kubota Co., Ltd. (Reference) 4D059 AA01 AA02 AA07 AA08 BA01 BA11 BA12 BA21 BC02 BE02 BE08 BE12 BE16 BE18 BE26 BE38 BE42 BE56 BE57 BE60 BF02 BF17 BJ00 BK11 BK12 BK17 CA01 CA11 DA03 DA15 DA16 DA17 DA22 DA23 DA24 DA43 EB06 4H061 AA02 CC35 CC51 CC55 DD20 GG13 GG17 GG19 GG22 GG41 GG49 GG50 GG54 HH41

Claims (3)

[Claims] When a plurality of kinds of organic wastes having different properties and concentrations are treated in the same treatment system and useful substances are collected, solid organic wastes such as garbage are led to a crushing step to crush the organic wastes. As a mixture with the organic waste in the form of sludge such as human waste, septic tank sludge, and the like, the crushed material is led to a two-pack coagulation dehydration step in which at least one of two kinds of coagulants having a phosphorus coagulation effect is added. Aggregate the phosphorus contained in, separate into solids containing aggregated phosphorus and desorbed liquid, guide the separated phosphorus-containing solids to the composting process, ferment under aerobic conditions, recover as compost A method for treating organic waste, comprising: conducting a desorbed liquid to an anaerobic fermentation step, fermenting under anaerobic conditions, and collecting biogas such as methane generated. 2. The organic waste is crushed in the crushing step by a compression crusher having a fine crushing discharge hole and performing compression crushing by a high pressure applied instantaneously. Organic waste treatment method. 3. The method for treating organic waste according to claim 1, wherein the organic waste having a low biodegradation rate is solubilized and liquefied before the two-pack coagulation dehydration step.