JPH11169896A - Filter of sludge contact tank and production of filler of sludge contact tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove the harmful fungis in sludge by mixing a magnesium compd., cellulose and chitin in the humus having the dominant bacteria including Bacillus and Actinomyces as the specifics of bacteria prepare the filler to be filled in a sludge contact tank. SOLUTION: The sludge treated in a sludge treating line W including a pretreating tank 10 and a biological treating tank 20 is introduced into the sludge receiving tank 40 of a sludge treating line C and sent to a sludge circulating tank 50. A part of the sludge is sent to a sludge contact tank 6 and brought into contact with a filler therein to dissolve the filler in the sludge, air is diffused to propagate the microorganism, and the sludge is returned to the sludge circulating tank 50. In this case, the filler is formed by mixing a magnesium compd., cellulose and chitin in the humus having the dominant bacteria including Bacillus and Actinomyces as the species of bacteria. Humic soil is exemplified as the humus, and the humus contg. Bacillus, Actinimyces or further Pseudomonoas as the species of bacteria is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a biological treatment of organic wastewater, in which sludge is filled in a sludge contact tank when the sludge is circulated between the sludge circulation tank and the sludge contact tank in the sludge treatment system. The present invention relates to a filler for positively growing dominant bacteria therein, and a method for producing the same.

[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 controlled by using an aerobic filter tank and an anaerobic filter tank to suppress odor, and is subjected to a sedimentation treatment 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 sludge in the sludge contact tank is insufficient, and the sludge treatment is insufficient. In some cases, there is a problem that harmful bacteria and organic nutrients in the sludge cannot be sufficiently removed. Then, when harmful bacteria and organic nutrients remaining in the sludge are returned to agricultural land, there is a problem that germination failure may be caused instead of contributing to growth as a fertilizer for agricultural products.

[0005] Therefore, the problem to be solved by the present invention is that, in a sludge treatment system, dominant bacteria such as Bacillus bacteria are actively multiplied in sludge circulated between a sludge circulation tank and a sludge contact tank. It is to remove harmful bacteria and organic nutrients sufficiently.

[0006]

Means for Solving the Problems To solve the above-mentioned problems, the invention according to claim 1 is directed to filling a sludge contact tank for circulating sludge with a sludge circulation tank in a sludge treatment system,
A filler for a sludge contact tank that comes into contact with sludge, characterized in that a humus having a dominant bacterium including a Bacillus bacterium and an actinomycete as a seed bacterium is mixed with a magnesium compound, cellulose, and chitin. The invention of Claim 2 is Claim 1
In the filler of the sludge contact tank according to, the humus,
It is characterized by mixing iron or iron compounds.

According to a third aspect of the present invention, there is provided the method for producing a filler for a sludge contact tank according to the first aspect, wherein the humus is mixed with the powder of the magnesium compound, the cellulose, and the chitin. And extruded with an extruder to form pellets.

[0008]

According to the first aspect of the present invention, the filler is filled in the sludge contact tank, and when the sludge enters the sludge contact tank and comes into contact with the filler, the 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 the sludge, 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 grow dominantly.

According to the second aspect of the present invention, the iron in the filler is combined with phosphorus contained in the sludge circulated from the sludge circulation tank to form a compound of iron and phosphorus (iron phosphate). to make. When this sludge is dehydrated, the iron phosphate in the sludge is contained on the dewatered sludge side, so that the phosphorus content on the desorbed water side is reduced. According to the third aspect of the present invention, the filler is formed into a pellet by an extruder.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a biological treatment apparatus for organic wastewater using a filler according to the present invention. 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 from the separation liquid tank 90, and then the wastewater is subjected to the biological treatment tank 20.
Biological treatment. The biological treatment tank 20 includes, firstly, a tank provided with an anaerobic filter bed tank, an aerobic filter bed tank, and a sedimentation tank, and second, a tank 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 solution 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, sludge and sludge are aerated, agitated, and settled, and led to the sludge receiving tank 40 of the sludge treatment system C.

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 diffusion tube 63 connected to a blower (not shown) is provided below the cartridge 65, and the inside is diffused by air sent from the air diffusion tube 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. The humus soil as the main raw material has a humus content of 8% or more and 35% of organic matter in the humus.
To the extent that this filler contains magnesium (M
g) A mixture of a compound, iron (Fe) or an iron compound, cellulose and chitin. The humus includes, for example, humus soil, and includes bacillus and actinomycete, as well as pseudomonas, filamentous fungi, and the like as inoculum.In particular, in the present invention, at least bacillus and actinomycetes among these bacteria are included. It is preferable that the bacterium is predominantly contained. As the inoculum of Bacillus and Actinomycetes in the humus, it is preferable that the number of Bacillus is, for example, 2.3 × 10 ³ cells / g or more. Even if the number of bacteria is small, it can grow as many dominant bacteria if environmental conditions are adjusted.

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, for example, Mg (OH) ₂ (magnesium hydroxide), magnesium carbonate (MgCO ₃ ), MgS
iO ₃ (magnesium metasilicate), CaMg (C
O ₃ ) ₂ (dolomite) is preferable 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%. In addition, Mg (OH)
₂ is insoluble in water, but when mixed as a humus, Mg can be mixed with sufficient stirring due to the characteristics of the humus.
^{As 2+} , it can be eluted into the sludge up to about 700 ppm.
It is easy to make it about ppm.

Examples of iron or iron compounds include iron compounds such as iron hydroxide and iron oxide, in addition to simple iron. 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.

[0021] Cellulose is widely distributed in plants and microorganisms in the natural world, but is mostly present in combination with lignin and pectin. 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 this filler, a powder of magnesium compound, iron or iron compound, cellulose and chitin is mixed with the humus and extruded by 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 pipe 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 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 bacteria 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 the 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 tolerate without taking nutrients. As a result, the sludge that has been rendered oligotrophic in the sludge contact tank 60 occupies the majority of sporulated Bacillus bacteria and the like.

Many Bacillus bacteria, actinomycetes and other Gram-positive bacteria secrete antibiotics, which break down 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 after this, the sludge rich in spores of Bacillus bacteria 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 operations, Bacillus and actinomycetes can be preferentially grown in the sludge in the sludge circulation tank 50, so that the harmful pathogenic gram-negative bacteria can be significantly reduced. it can.

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 (for example, about 85% water). .

By reducing the dehydrated cake to agricultural land, soil improvement can be achieved, which can contribute to the growth of agricultural products. 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 in agricultural land itself can be a nutrient source for agricultural crops, and when nutrients such as fertilizers are additionally given to the soil, sporulated Bacillus and actinomycetes, which are present in a large amount in sludge, can be obtained. Are activated by the nutrients of the fertilizer and proliferate 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 on agricultural land have cell membranes formed of chitin, and the enzymes produced by actinomycetes in sludge prefer 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 then 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 is crushed by drying to be granular or powdery,
It can be in a form that is easy to mix with farmland.

[0037]

According to the first aspect of the present invention, Bacillus bacteria, actinomycetes and the like in humus can be predominantly grown as seeds in sludge. Thereby, the harmful bacteria in the sludge can be sufficiently removed. According to the second aspect of the present invention, a compound of phosphorus and iron is contained in the dewatered sludge side during the dewatering of the sludge by forming a compound of phosphorus in the sludge and iron in the filler. Can be reduced in phosphorus content. According to the third aspect of the present invention, a pellet-like filler can be formed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a biological treatment apparatus for organic wastewater using a filler according to the present invention.

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

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[Procedure amendment]

[Submission date] January 30, 1998

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Title of Invention] sludge contact tank filler, and a manufacturing method of sludge contact tank filler

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tokuaki Itoi 1-10-14 Hamamatsucho, Minato-ku, Tokyo Sumitomo Higashi Shimbashi Building No. 3 In 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 1-27-27 Konan, Minato-ku, Tokyo Inside Ebara Corporation (72 ) Inventor Akira Ichihara 1-6-27 Konan, Minato-ku, Tokyo Inside Ebara Manufacturing Co., Ltd. (72) Inventor Kunitake Suzuki 7-14-1 Ginza, Chuo-ku, Tokyo Inside Ebara Corporation (72) Invention Person Yoshihiro Kosaka 7-14-1 Ginza, Chuo-ku, Tokyo Inside Ebara Corporation

Claims (3)

[Claims] 1. A filler for a sludge contact tank, which is filled in a sludge contact tank for circulating sludge with a sludge circulation tank in a sludge treatment system and comes into contact with sludge, wherein the filler contains Bacillus bacteria and actinomycetes. A filler for a sludge contact tank, wherein a humus having a bacterium as a seed bacterium is mixed with a magnesium compound, cellulose and chitin. 2. The filler for a sludge contact tank according to claim 1, wherein iron or an iron compound is mixed with the humus. 3. The method for producing a filler for a sludge contact tank according to claim 1, wherein each of the magnesium compound, the cellulose, and the chitin powder is mixed with the humus, and the mixture is fed to an extruder. A method for producing a filler for a sludge contact tank, wherein the filler is extruded and pelletized.