JP3187363B2 - Manufacturing method of soil conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biological treatment of organic wastewater, in which sludge is circulated between a sludge circulation tank and a sludge contact tank in a sludge treatment system, and a dominant bacterium is proliferated in the sludge. The present invention relates to a method for producing a soil conditioner for producing a soil conditioner from sludge.

[0002]

2. Description of the Related Art Conventionally, a biological treatment method is known as a technique for decomposing and removing organic substances in organic wastewater such as sewage. In this biological treatment method, first, organic wastewater is pretreated in a wastewater treatment system, and then this wastewater is biologically treated. In this biological treatment, for example, sewage is treated using an aerobic filter tank and an anaerobic filter tank, and at the same time, a bad smell is suppressed, and a sedimentation treatment is performed in a sedimentation tank, and the treated water generated here is discharged after disinfection. . Then, the sludge generated in the anaerobic filter tank or the sedimentation tank is sent to a sludge treatment system, circulated between the sludge circulation tank and the sludge contact tank, and diffused in the sludge contact tank.

[0003] In this case, the sludge contact tank is filled with a filler (humic pellets), and the sludge is brought into contact with the filler to allow the dominant bacteria of Bacillus and actinomycetes to proliferate in the sludge. Kills harmful bacteria. The sludge treated here is further concentrated in a sludge concentration tank and stored in a sludge storage tank, or dewatered by a dehydrator. And the sludge obtained here is returned to farmland as a soil conditioner.

[0004]

However, in the above-mentioned conventional technology, the growth of dominant bacteria such as Bacillus in the sludge in the sludge contact tank is insufficient, or the operation of the sludge treatment system is difficult. There is a problem that harmful bacteria in the sludge may not be sufficiently removed when it is insufficient or the like. And, when harmful bacteria remaining in sludge are returned to agricultural land, there is a problem that germination failure may be caused instead of contributing to growth as fertilizer for agricultural products.

[0005] Therefore, the problem to be solved by the present invention is to preferentially and actively multiply Bacillus bacteria and the like in sludge in a sludge treatment system, sufficiently remove harmful bacteria, and reduce sludge to agricultural land. To produce a suitable soil conditioner.

[0006]

Means for Solving the Problems] To solve the problems described above, in the present invention, occur in biological treatment of organic wastewater
Sludge is circulated between the sludge circulation tank and the sludge contact tank.
And remove the treated sludge from the sludge circulation tank
A method for producing a soil conditioner from sludge, comprising the step of:
Feeding a part of the sludge in the circulation tank to the sludge contacting vessel, the in-fouling <br/> mud contacting vessel, humus and magnesium compound having Yuuranaikin comprising Bacillus subtilis and actinomycetes as an inoculum, cellulose and it is contacted with a filler mixed and chitin, performs aeration treatment, the treated sludge is returned to the sludge circulation tank circulation
A method for producing a soil conditioner characterized by performing a treatment .
Things.

[0007] In the method for producing a soil improvement agent, the sludge of the sludge contacting vessel to poor nutritional status, it is possible to return the sludge the Bacillus and the actinomycetes were spores into the sludge circulation vessel, also , removed from the sludge circulation vessel
Processing sludge can be dehydrated, it can be dried to dehydration treatment sludge.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, when sludge comes into contact with a filler in a sludge contact tank, humus and the like of the filler are dissolved in the sludge. Seed bacteria such as Bacillus bacteria in the filler are supplied with nutrients from sludge, and sporulated seed bacteria germinate, become active, and proliferate. In addition, the magnesium compound and cellulose in the filler work to promote the growth of Bacillus bacteria, and the magnesium compound and chitin work to promote the growth of actinomycetes. Therefore, in the sludge contact tank, Bacillus bacteria and actinomycetes proliferate dominantly. By returning this sludge to the sludge circulation tank and repeating the above operation, sludge rich in dominant bacteria such as Bacillus bacteria can be produced.

In the present invention, the sludge is circulated in the sludge contact tank. However, if the nutrient supply to the microorganisms is small, the microorganisms take up the nutrients in the sludge. Naturally becomes oligotrophic, and after the oligotrophic state, the bacteria in the sludge self-digest and decrease significantly,
Bacillus bacteria and the like exist as spores so that they can be tolerated without taking nutrients. Therefore, in the sludge that has become oligotrophic in the sludge contact tank, spores of Bacillus bacteria and the like increase, and by returning this sludge to the sludge circulation tank, the spores of Bacillus bacteria and the like are excellent. The sludge rich in bacteria is returned to the sludge circulation tank.

The sludge taken out of the sludge circulation tank is:
Is dehydrated with a dehydrator becomes to case gaseous. When the dehydrated sludge is further dried, general bacteria in the sludge are killed, but sporulated Bacillus bacteria and the like are not killed. Therefore, spores of Bacillus bacteria and the like in the sludge by the drying treatment are present as they are, and other bacteria are killed. Also,
The water content is reduced, the weight is reduced, the material is easily transported, and it becomes granular or powdery so that it can be easily mixed with farmland.

[0011] below, with reference to the drawings, a description will be given of an embodiment of the present invention. FIG. 1 is a block diagram showing an embodiment of an organic wastewater biological treatment apparatus to which a method for producing a soil conditioner according to the present invention is applied. In the figure, the upper side of the two-dot chain line shows the sewage treatment system W, and the lower side shows the sludge treatment system C.
In the sewage treatment system W, the organic sewage is put into the pretreatment tank 10 and mixed with the separation liquid containing humus and / or the sludge containing humus, and then the sewage is biologically treated in the biological treatment tank 20. First, examples of the biological treatment tank 20 include those provided with an anaerobic filter bed tank, an aerobic filter bed tank, and a sedimentation tank.
Secondly, there is one provided with a batch tank.

In the former, for example, sewage is treated with anaerobic microorganisms in an anaerobic filter tank, then treated with aerobic microorganisms in an aerobic filter tank, and a part of the mixed liquid in the aerobic filter tank is treated. Is returned to the anaerobic filter tank to suppress odor in the anaerobic filter tank. Then, after the other mixed solution is introduced into the sedimentation tank to settle the sludge, the treated water is disinfected in the disinfection tank 30 and discharged. In addition, the sludge generated in the anaerobic filter bed tank or the settling tank is guided to the sludge receiving tank 40 of the sludge treatment system C. On the other hand, in the latter case, for example, the sludge is aerated, stirred and settled, and the sludge treatment system C
To the sludge receiving tank 40.

When the sludge treated in the sewage treatment system W is guided to the sludge receiving tank 40 of the sludge treatment system C, it is further sent to the sludge circulation tank 50. Then, a part of the sludge is sent from the sludge circulation tank 50 to the sludge contact tank 60, and the sludge is brought into contact with the filler in the sludge contact tank 60 to dissolve the filler in the sludge, diffused, and subjected to aeration treatment to grow microorganisms. Is carried out again and the sludge circulation tank 50
Return to. The treated sludge is sent from the sludge circulation tank 50 to the sludge concentration tank 70 to be concentrated, and the concentrated sludge is sent to the sludge storage tank 80.

A separating liquid tank 90 is connected to the sludge circulating tank 50, and a part of the sludge is sent from the sludge circulating tank 50 to the separating liquid tank 90, and the sludge settled in the lower part of the separating liquid tank 90 (solids). Is returned to the sludge circulation tank 50, and the separated liquid containing humus and / or the sludge containing humus is returned to the pretreatment tank 10 of the sewage treatment system W. When the separation liquid tank 90 is not provided, the separation liquid tank 90 may be directly returned from the sludge circulation tank 50 to the pretreatment tank 10. The dewatering machine 100 is for dewatering sludge into a cake form, for example, a screw dewatering machine,
Examples include a vacuum dehydrator and a centrifugal separator. Further, the dryer 110 dries the sludge dehydrated by the dehydrator 100.

FIG. 2 is a sectional view showing a detailed configuration of the sludge contact tank 60 of FIG. The upper part of the tank body 61 of the sludge contact tank 60 has a circulation pipe 6 into which sludge enters from the sludge circulation tank 50.
2a is provided, and a circulation pipe 62b for returning sludge to the sludge circulation tank 50 is provided below the tank main body 61. Inside the tank main body 61, a cartridge 65 partitioned by a wire mesh or the like is fixed on a base 64 provided on the inner peripheral wall at the center, and a filler described later is packed in the cartridge 65.

An air diffuser 63 connected to a blower (not shown) is provided below the cartridge 65, and the inside is diffused by air sent from the air diffuser 63. Further, an air lift pump 66 is provided in the sludge contact tank 60, and the sludge in the lower part of the tank is taken in from the inflow port 66a, pulled up to the upper part of the tank, and discharged from the outflow port 66b. Circulate.

Next, the cartridge 65 of the sludge contact tank 60
The filler to be filled in the inside will be described. This filler is
It is a mixture of humus, magnesium (Mg) compound, iron (Fe) or iron compound, cellulose and chitin. Examples of the humus include humus soil, and include bacillus and actinomycetes as well as Pseudomonas and filamentous fungi as a seed fungus.
Among these bacteria, those containing at least Bacillus bacteria and actinomycetes are preferred. As the seed bacteria of Bacillus bacteria and actinomycetes in humus, Bacillus bacteria are, for example, 2.3 × 10 ³ bacteria. / G or more. This number of bacteria is not necessarily large, but if environmental conditions are adjusted, many bacteria can grow as dominant bacteria.

The magnesium compound contains Mg ²⁺ and includes, for example, magnesium hydroxide and magnesium carbonate. It is preferable that the magnesium compound be dissolved in the sludge in a required amount according to the amount of the dissolved humus, and the humus and the magnesium compound always coexist in the sludge. In example MgSO 4 · _7H 2 _O, solubility is high, when mixed in the filler, the shape of the filler by contact with the sludge rapidly disintegrating, filler would be dissolved in a short period of time, long-term use Can not do.

On the other hand, Mg (OH) ₂ (magnesium hydroxide), magnesium carbonate (MgCO ₃ ), MgSiO ₃
(Magnesium metasilicate), CaMg (CO ₃ )
₂ (dolomite) is preferred because it has low solubility and dissolves in sludge at substantially the same rate as humus. For example, Mg
(OH) ₂ is insoluble in water, and the hardness of the filler increases even when mixed with humus, so that its shape can be maintained even in the sludge contact tank 60 (in the sludge).

Further, the magnesium compounds in the sludge contact tank 60, at least 0.5ppm or more as ^{Mg 2+,} usually good for about 2ppm are continuous dissolution in the sludge from the filler, to this way, from the ratio of the dissolution loss of sludge and filler passing through, as Mg ²⁺ fillers 1
What is necessary is just to make it contain about 3%. Mg (OH) ₂ is insoluble in water, but when mixed with humus, it can be eluted into sludge up to about 700 ppm as Mg ²⁺ if sufficiently stirred, so that stirring is adjusted. It is easy to make the elution amount about 2 ppm.

The iron or iron compound may be, for example, iron compounds such as iron hydroxide and iron oxide, in addition to iron alone. The reason why iron is mixed with the filler is that phosphorus contained in the sludge circulated from the sludge circulation tank 50 forms a compound of iron and phosphorus or a complex compound with humic substances, and then forms dehydrated sludge. This is for reducing the phosphorus content on the desorbed water side by containing it on the desorption side.

[0022] Cellulose is widely distributed in plants and microorganisms in the natural world, but is mostly present in combination with lignin, pectin and the like. Industrially, most are obtained from wood, and are obtained by purifying defatted cotton and wood pulp, and commercially available products formed in powder form can be used. Chitin is a nitrogen-containing polysaccharide that is present in shellfish and fungi such as crab, shrimp, krill and yeast, and includes, for example, chitin and chitosan. Can be used. These celluloses and chitins are
Since it is for growing Bacillus and actinomycetes in the humus in the initial stage, it is sufficient to add a small amount to the humus.

As a method for producing the filler, a powder of a magnesium compound, an iron or iron compound, cellulose and chitin is mixed with the humus and extruded with an extruder to be naturally solidified. It can be in the form of pellets.

A part of the sludge is sent from the sludge circulation tank 50 to the sludge contact tank 60, mixed in the sludge contact tank 60 for a predetermined time, and returned to the sludge circulation tank 50 again. When the sludge is mixed in the sludge contact tank 60, the circulation of the sludge between the sludge circulation tank 50 and the sludge contact tank 60 is stopped,
No new sludge is sent from the sludge circulation tank 50 into the sludge contact tank 60.

In the sludge contact tank 60, the sludge is diffused by air from the diffuser 63, and is circulated by the air lift pump 66 while being in contact with the filler. Immediately after moving into the sludge contact tank 60, the sludge is in a eutrophic state, so that the inoculum such as Bacillus in the filler is activated by contact with the sludge and absorbs nutrients in the sludge. Proliferate.

Further, the magnesium compound and the cellulose in the filler work to promote the growth of Bacillus bacteria, and the magnesium compound and chitin work to promote the growth of actinomycetes. Therefore, in the sludge contact tank 60, the Bacillus bacteria and actinomycetes are proliferated significantly more predominantly due to the presence of the magnesium compound, cellulose, and chitin in the filler than in the absence of these. Furthermore, Bacillus bacteria and the like, proteins in sludge, starchy,
Decomposes fats and oils and odorous components. In addition, when the activity of Bacillus bacteria or the like is activated in the sludge, a part of the lignin in the sludge is combined with a protein to change into humus.

There are various bacteria other than Bacillus bacteria in the sludge, and these bacteria also absorb nutrients and grow in the eutrophic sludge. Therefore, various bacteria multiply until the nutrients in the sludge disappear, that is, until the sludge changes from the eutrophic state to the oligotrophic state.

However, since the sludge in the sludge contact tank 60 is only a fixed amount sent from the sludge circulation tank 50, the nutrient supplied to each bacterium from the sludge is limited to a fixed amount. Therefore, the sludge immediately after being sent from the sludge circulation tank 50 is in a eutrophic state, but if the sludge is circulated in the sludge contact tank 60, when each bacterium takes in nutrients in the sludge and multiplies, The sludge in the sludge contact tank 60 naturally becomes oligotrophic.

When the sludge becomes oligotrophic, the Bacillus and actinomycetes sporulate so that they can withstand without taking nutrients. As a result, in the sludge that has become oligotrophic in the sludge contact tank 60, spores of Bacillus bacteria and the like occupy the majority.

Many Bacillus bacteria, actinomycetes and other Gram-positive bacteria secrete antibiotics, which degrade the cell membrane of Gram-negative bacteria such as Escherichia coli and kill Gram-negative bacteria. In addition, many gram-negative bacteria cannot be sporulated, and many of them die under oligotrophic conditions.

The sludge is circulated in the circulating contact tank 60 until the above condition is reached. This makes it possible to positively maintain dominant bacteria such as Bacillus bacteria and actinomycetes. Here, the time required until the inside of the sludge contact tank 60 is put into an oligotrophic state to spore-form Bacillus bacteria and the like is determined by the amount of sludge charged into the sludge contact tank 60 and the time required to circulate the sludge in the sludge contact tank 60. And adjust it. Then, if the sludge is returned to the sludge circulation tank 50 thereafter, the sludge rich in spores and bacilli and actinomycetes will germinate and activate in the sludge circulation tank 50 and grow again.

When the sludge is returned from the sludge contact tank 60 to the sludge circulation tank 50, the sludge mixes with the other sludge in the sludge circulation tank 50, so that the sporulated Bacillus bacteria and the like in the returned sludge are removed. Once again, they will be placed under eutrophication, break through the spore shell, begin to reactivate and multiply. After this,
Again, part of the sludge from the sludge circulation tank 50 is removed from the sludge contact tank 60.
And perform the above operations. By repeating the above operation, Bacillus bacteria and actinomycetes can be preferentially grown in the sludge in the sludge circulation tank 50, so that harmful gram-negative bacteria can be significantly reduced.

The sludge treated as described above is concentrated in a sludge concentration tank 70 and stored in a sludge storage tank 80, or dewatered by a dehydrator 100 to form a cake (eg, about 85% water). .

By returning this dehydrated cake to agricultural land, soil improvement can be achieved, which can contribute to growing crops. In addition, this dewatered cake may be sown on farmland as it is, and may be stirred with a tiller, for example.

The dehydrated cake reduced to agricultural land can itself be a nutrient source for agricultural crops. Further, when a nutrient source such as fertilizer is given to the soil together, sporulated Bacillus bacteria and actinic radiation which are present in a large amount in the sludge can be obtained. The fungus is activated by the nutrients of the fertilizer and grows again. In addition, by reducing humic substances and sludge containing a large number of bacillus-preferring bacillus bacteria on agricultural land, the pH buffering capacity increases in the soil, the oxygen concentration in the soil increases, and the aggregate structure of the soil increases. It contributes to the growth of crops and the control of pathogenic bacteria.

Soil pathogens such as Fusarium and Rhizoctonia existing in farmland have a cell membrane formed of chitin, and the enzyme produced by actinomycetes in sludge prefers chitin. Dissolved by enzymes. In addition, soil pathogenic bacteria such as phytofutra and picium are lysed by Bacillus bacteria that prefer cellulose because the cell membrane is formed of cellulose. Therefore,
This sludge kills various soil pathogens in farmland,
By suppressing the growth of soil pathogens, it is possible to reduce the disease of agricultural crops and prevent soil hardening. Furthermore, the odor can be made aromatic by increasing the growth of Gram-positive bacteria, the generation of malodor due to the decomposition and decomposition of Gram-negative bacteria can be suppressed, and the odor can be eliminated from the soil.

As the soil conditioner, the sludge may be directly returned to the agricultural land, but it is more preferable that the sludge is dewatered by the dehydrator 100 and further dried by the dryer 110 to be returned to the agricultural land. That is, even when the sludge circulation tank 50 and the sludge contact tank 60 are treated as described above, there is a possibility that the pathogenic bacteria are alive without dying in the sludge. In such a case, when the dehydrated sludge is dried at, for example, 100 ° C., vegetative cells of general bacteria are killed, but sporulated Bacillus bacteria and the like are not killed. Therefore, by the drying treatment, the spore-forming Bacillus bacteria and the like in the sludge can be kept as they are, and only the pathogenic bacteria can be killed. Further, by drying the dewatered sludge, the water content is reduced, the weight is reduced, and the sludge is easily transported, so that the handling property can be improved.
In addition, it can be pulverized by drying to be granulated or powdery, and can be easily mixed with farmland.

[0038]

According to the first aspect of the present invention, a soil conditioner can be produced from sludge in which Bacillus bacteria, actinomycetes and the like are proliferated. Thereby, various pathogenic bacteria (gram-negative bacteria) in the soil are killed by the Bacillus bacteria and actinomycetes in the soil conditioner, and the growth of the soil pathogenic bacteria is suppressed, so that the disease of agricultural crops can be reduced. At the same time, soil hardening can be prevented. Further, by promoting the growth of Gram-positive bacteria, the smell can be made aromatic, the generation of malodor due to the decomposition and decomposition of Gram-negative bacteria can be suppressed, and the odor can be eliminated from the soil. Further, the pH buffering capacity increases in the soil, the oxygen concentration in the soil increases, the aggregate structure of the soil can be achieved, and it can contribute to the growth of agricultural crops and the control of pathogenic bacteria.

According to the second aspect of the present invention, it is possible to positively maintain and grow dominant bacteria such as Bacillus. According to the invention of claim 3, the soil conditioner can be made into a cake. According to the invention of claim 4, the spores of Bacillus bacteria and the like in the sludge can be allowed to exist as they are, and the pathogenic bacteria can be killed. it can. Also,
The weight can be reduced, the material can be easily transported, and since it is granular or powdery, it can be made into a form that can be easily mixed with farmland.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an organic wastewater biological treatment apparatus to which a method for producing a soil conditioner according to the present invention is applied.

FIG. 2 is a sectional view showing a detailed configuration of the sludge contact tank of FIG.

[Explanation of symbols]

 Reference Signs List 10 pretreatment tank 20 biological treatment tank 30 disinfection tank 40 sludge receiving tank 50 sludge circulation tank 60 sludge contact tank 61 tank body 62a, 62b circulation pipe 63 diffuser pipe 64 units 65 cartridge 66 air lift pump 66a inlet 66b outlet 70 sludge concentration tank 80 Sludge storage tank 90 Separation liquid tank 100 Dehydrator 110 Dryer C Sludge treatment system W Sewage treatment system

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noriaki Itoi 1-10-14 Hamamatsucho, Minato-ku, Tokyo Sumitomo Higashi-Shimbashi Building No. 3 Inside the Japan Agricultural Village Drainage Association (72) Inventor Hiroshi Kawashige Tokyo 1-10-14, Hamamatsucho, Minato-ku Sumitomo Higashi-Shimbashi Building No. 3 Inside the Japan Agricultural Village Drainage Association (72) Inventor Takayuki Kata 1-27, Konan, Minato-ku, Tokyo Ebara Manufacturing Co., Ltd. 72) Inventor Akira Ichihara 1-6-27 Konan, Minato-ku, Tokyo Inside Ebara Corporation (72) Inventor Kunitake Suzuki 7-14-1, Ginza, Chuo-ku, Tokyo Inside Ebara Business Co., Ltd. (72) Inventor Yoshihiro Kosaka 7-14-1, Ginza, Chuo-ku, Tokyo Inside Ebara Business Co., Ltd. (56) References JP-A-5-31490 (JP, A) JP-A-4-284894 (JP, A) JP-A-61-263697 (JP, A) JP-A-52-656 (JP, A) JP-A-8-99074 (JP, A) JP-A-53-7471 (JP, A) A) JP-A-6-346054 (JP, A) JP-A-9-234454 (JP, A) JP-A-9-239396 (JP, A) JP-A-60-129193 (JP, A) JP-A-63 JP-A-85080 (JP, A) JP-A-63-147887 (JP, A) JP-A-6-87000 (JP, A) JP-A-1-96284 (JP, A) JP-A-9-122682 (JP, A) JP-A-11-147781 (JP, A) JP-A-10-84947 (JP, A) JP-A-10-57994 (JP, A) JP-A-10-490 (JP, A) 11677 (JP, B2) JP 5-51038 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09K 17/00-17/52 C02F 11/00-11/20 C05B 1/00-C05G 5/00

Claims (4)

(57) [Claims] 1. Occurs in biological treatment of organic wastewater
The sludge is circulated between the sludge circulation tank and the sludge contact tank.
Sludge to be treated from the sludge circulation tank
The method for producing a soil conditioner from
Feeding a part of the sludge in the tank to the sludge contacting vessel, in the sludge contacting vessel, humus and magnesium compound having Yuuranaikin comprising Bacillus subtilis and actinomycetes as an inoculum, mixed with cellulose and chitin is contacted with the filler, subjected to aeration treatment, the treated sludge is circulated process and return to the sludge circulation vessel
A method for producing a soil conditioner. 2. The method for producing a soil conditioner according to claim 1, wherein the sludge in the sludge contact tank is rendered oligotrophic,
A method for producing a soil conditioner, comprising returning sludge formed by spore formation of the Bacillus bacteria and the actinomycetes to the sludge circulation tank. 3. A method for producing a soil improvement agent according to claim 1 or 2, the processing stain was removed from the sludge circulation vessel
A method for producing a soil conditioner, comprising dehydrating mud . 4. The method for producing a soil improvement agent according to claim 3, the manufacturing method of soil improvement agent, which comprises drying the dehydrated sludge.