JP2002177979A - Waste water treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide waste water treatment equipment which is capable of making efficiently treatment of organic waste water, reducing a running cost and equipment cost and reducing the amount of the sludge to be generated as a whole or making the material zero. SOLUTION: This waste water treatment equipment is provided with a biological treating vessel which is packed with biological carriers for aerobically and biologically treating the organic matter in the organic waste water, a sludge separating means which separates the solid from a liquid mixture composed of the sludge after the biological treatment and the treated water, a circulating flow passage which circulates part of the separated sludge to the biological treating vessel, a sludge treating vessel which aerobically and biologically treats the remaining separated sludge under higher temperature conditions than those of the biological treating vessel and a high-temperature sludge circulating flow passage which circulates the sludge after the high-temperature biological treatment to the biological treating vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wastewater treatment apparatus for biologically treating organic wastewater, and more particularly to a wastewater treatment apparatus for reducing the volume of sludge generated in biological treatment.

[0002]

2. Description of the Related Art Conventionally, as an aerobic biological treatment apparatus for organic wastewater such as sewage, food wastewater, kitchen wastewater or septic tank sludge, an activated sludge treatment apparatus, a fixed-bed biological treatment apparatus or a fluidized-bed treatment apparatus is known. Used.

[0003] In the activated sludge treatment apparatus, wastewater is supplied into a treatment tank in which activated sludge, which is an aerobic microorganism, floats, and is aerated with air. It is a device that oxidatively decomposes organic matter biologically.In the case of a fixed-bed type biological treatment device, a fixed bed of biological carriers is provided in a treatment tank, and microorganisms are applied to the surface of the carrier by aeration with air. It is a device that biologically oxidizes and decomposes organic matter in raw water by the biological action of attached microorganisms by adhering and growing, and the fluidized bed type treatment device can flow into the liquid in the aerobic biological treatment tank. A device that oxidizes and decomposes organic matter in raw water by the biological action of microorganisms that adhere to and grow on the surface of the fluidized biological carrier by supplying raw water and aerating the air with raw water. It is.

[0004] In any of the above-mentioned biological treatment apparatuses, a large amount of microorganisms proliferated as sludge is generated as biological substances are biologically decomposed. The generated sludge is separated and concentrated in a sedimentation tank and the like, and a part of the sludge is circulated to the biological treatment step, while the remainder is discharged outside the system as surplus sludge and disposed of by an appropriate method. The surplus sludge amount is 30 to 4 times the amount of organic matter (BOD) in the raw water introduced into the biological treatment process.
It is said to be 0%. As a method of disposing of the excess sludge, the sludge is concentrated and dewatered and then disposed of by incineration or landfill, or the volume is reduced by anaerobic digestion.

Further, as a method for reducing the volume of generated sludge as much as possible, Japanese Patent Publication No. Hei 6-509996 discloses a combination of a mesophilic biological treatment tank and a thermophilic biological treatment tank to reduce sludge generated from the mesophilic biological treatment tank. A method for reducing the volume of sludge that is solubilized in a thermophilic biological treatment tank and then returned to a medium-temperature biological treatment tank is disclosed, and Japanese Patent No. 2973761 discloses:
There is disclosed a method for reducing the volume of sludge that is obtained by extracting sludge from an aeration tank, solubilizing the sludge by ozone treatment, and then returning the sludge to an aeration tank for treatment.

[0006]

According to the conventional method for disposing of excess sludge, the sludge is concentrated and dewatered and then incinerated or landfilled. The bulk is large because it is as high as 80 wt%,
In the case of requesting disposal from a waste disposal company, the cost of picking up becomes high, and at present, it accounts for much of the cost of wastewater treatment as a whole. Furthermore, in landfill disposal, the remaining years of the industrial waste landfill are decreasing, and the collection cost is increasing year by year. In addition, in the case of incineration, fuel consumption is high due to high water content and fuel cost is high.Furthermore, it is necessary to treat exhaust gas and incineration ash. It is a situation that is becoming more common.

In the method of reducing the volume by the anaerobic digestion method, sludge is supplied into a treatment tank in which anaerobic microorganisms such as methane bacteria float, and the mixture is aerated and stirred with anaerobic gas. This is a method of decomposing organic substances in sludge into methane gas or carbon dioxide gas by the biological action of anaerobic microorganisms, and has the advantage that methane gas can be effectively used as fuel, but it takes a long time to process, so digestion tanks etc. The facilities described above become excessively large, and the amount of sludge finally generated is also large, and the disposal cannot solve the above-mentioned problems.

Further, in the sludge volume reduction method disclosed in Japanese Patent Publication No. 6-509996 and Japanese Patent No. 2973761, biological treatment tanks such as a medium-temperature biological treatment tank and an aeration tank for aerobic biological treatment of organic matter. However, because the activated sludge floc is a floating treatment tank, it is a major microorganism that prey on organic matter in wastewater and solubilized sludge and biologically oxidatively decompose. Is also supplied to the solubilization treatment step and is killed and decomposed by the solubilization treatment, so that the proliferation is small, and therefore, the treatment efficiency of organic substances is reduced, and there is a problem that the biological treatment tank becomes excessively large and the treatment time is increased. In addition, in the sludge volume reduction method disclosed in Japanese Patent Application Laid-Open No. 6-509986, since the treatment is performed by a plurality of cycle operations, there is a problem that the treatment process is complicated and the treatment time is further increased. Patent No. 2
The method disclosed in Japanese Patent No. 973761 does not effectively use oxygen in the ozone-containing gas, so that there is a problem that equipment costs and operating costs increase. Especially in the biological treatment tank after sludge volume reduction treatment, the load in the treatment tank increases,
There is a problem that more oxygen is required and the operation cost increases.

The present invention has been made in view of the above-mentioned problems in the conventional sludge disposal and volume reduction treatment, and can perform highly efficient treatment of organic wastewater, as well as operating costs and equipment. The purpose of the present invention is to provide a wastewater treatment apparatus capable of reducing costs and the like and further reducing or eliminating the amount of sludge generated as a whole.

[0010]

The gist of the present invention to achieve the above object is to provide a wastewater treatment apparatus for aerobic biological treatment of organic matter in organic wastewater, according to the first aspect of the present invention. Biological treatment tank filled with biological carriers for aerobic biological treatment of organic substances in effluent wastewater, sludge separation means for solid-liquid separation of a mixed liquid of sludge after biological treatment and treated water, and biological separation of part of the separated sludge A circulation channel that circulates to the treatment tank, a sludge treatment tank that aerobicly treats the remaining separated sludge at a higher temperature than the biological treatment tank, and a high-temperature treatment sludge circulation that circulates the sludge after the high-temperature biological treatment to the biological treatment tank A wastewater treatment apparatus characterized by comprising a flow path.

[0011] In a second aspect of the present invention, there is provided a wastewater treatment apparatus for aerobic biological treatment of organic matter in organic wastewater, a biological treatment tank for aerobic biological treatment of organic matter in organic wastewater, Sludge separation means for solid-liquid separation of the mixed liquid of treated sludge and treated water, sludge re-aeration tank filled with biological carrier for aerobic biological treatment of part of the separated sludge, and biological treatment of the remaining separated sludge A sludge treatment tank that performs aerobic biological treatment at a higher temperature than the tank, a high-temperature treated sludge supply channel that supplies the sludge after the high-temperature biological treatment to the sludge re-aeration tank, and a sludge that has been subjected to the sludge re-aeration treatment to the biological treatment tank. A wastewater treatment apparatus comprising a re-aeration sludge circulation channel that circulates.

According to the third aspect of the present invention, the biological treatment tank and / or the sludge re-aeration tank in the wastewater treatment apparatus according to the first or second aspect of the present invention has a flow path filled with a biological carrier in a flowable manner. In the invention according to claim 4, the sludge separating means in the wastewater treatment apparatus according to claim 1, 2, or 3 includes a settling tank and a sludge concentration apparatus. These are combined means.

In the present invention, when a biological carrier is used as a fluidized bed, a synthetic resin such as polyethylene, polypropylene, or vinyl chloride may have a specific gravity of 0.9.
It is preferable to use a carrier prepared in the form of a hollow cylinder having a diameter of 2 to 15 mm, which is preferable from the viewpoint of adhesion and growth of microorganisms, retention and fluidity, but may be in the form of particles or the like. The material may be an organic substance other than the synthetic resin, or an inorganic substance such as activated carbon. Further, when the biological carrier is used as a fixed bed, a carrier or a long fiber bundle formed in an appropriate shape with a synthetic resin or the like of the material is preferable,
Inorganic substances such as ceramics may be used. Therefore, the biological carrier in the present invention is not limited to the above-mentioned material and shape, as long as the microorganism can adhere and grow thereon. The amount of the biological carrier to be filled is 2 to the liquid volume in the treatment tank.
It is preferable to fill from 0 to 60%.

It is preferable that the treatment temperature in the biological treatment tank is maintained at 10 to 50 ° C., and the treatment temperature in the sludge treatment tank is maintained at 55 to 75 ° C. The sludge concentration in the sludge treatment tank is 1 to 10 vol%. , A residence time of 10
It is preferable to perform the treatment for about 50 hours. Further, as a sludge separating means, a sedimentation tank, a membrane separator, a centrifugal separator,
A sludge concentrator such as a filtration device or a combination thereof can be used.

As described above, the present invention is configured as an aerobic biological treatment tank or a re-aeration tank filled with a biological carrier, thereby preying on organic matter in wastewater and organic matter in solubilized sludge to produce biological matter. The major microorganisms that are oxidatively decomposed into large organisms, such as the beetle and the viper beetle, efficiently adhere to and grow on the carrier surface, and are retained in the treatment tank, supplied to the solubilization process, and not solubilized. Proliferates efficiently and decomposes organic matter efficiently.
Therefore, the processing efficiency of organic substances is high, and the size of the processing tank and the processing time can be reduced. In addition, a sludge treatment tank for aerobic biological treatment of sludge at a higher temperature than that of the biological treatment tank will be provided. Suspended microorganisms will be efficiently killed and decomposed to lower molecular weight (solubilized), and the solubilized sludge will be circulated. By doing
The volume of sludge generated as a whole can be reduced or eliminated.

According to the third aspect of the present invention, since the biological treatment tank and / or the sludge re-aeration tank is a fluidized bed treatment tank, the efficiency of contact between microorganisms and wastewater or sludge is increased, and furthermore, large-sized microorganisms are treated. Predation of organic matter and solubilized sludge is efficiently performed by the multiplication of the water. Further, in the invention described in claim 4, the sludge separating means is a means combining a settling tank and a sludge concentrating device, whereby the sludge is concentrated to a high concentration, and the solubilization of the sludge can be promoted. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of a wastewater treatment device according to one embodiment of the present invention, FIG. 2 is a system diagram of a wastewater treatment device according to another embodiment, and FIG. 3 is a diagram of a wastewater treatment device according to another embodiment. It is a system diagram. In all the drawings, members having the same action are denoted by the same reference numerals.

Reference numeral 1 denotes an adjusting tank for adjusting the amount of waste water supplied to the subsequent processing tank, and if necessary, equipment for adjusting the pH with an alkali or the like may be provided. The liquid 2 is filled with a biological carrier 7 so as to be able to flow into a liquid, and aerobic microorganisms adhere to and grow on the biological carrier 7 and float, and are aerated with an oxygen-containing gas. Is a fluidized-bed biological treatment tank (hereinafter simply referred to as a treatment tank) for oxidatively decomposing organic substances, and the treatment tank 2 is divided into two chambers in a horizontal direction by a partition wall. Or a combination of a fluidized bed biological treatment tank and an activated sludge treatment tank not filled with the biological carrier 7.

As the biological carrier 7 to be filled in the treatment tank 1, a synthetic resin such as polyethylene, polypropylene, or vinyl chloride is prepared to have a specific gravity of 0.9 to 1.2 and has a diameter of 2 to 15%.
The use of a carrier formed in a hollow cylindrical shape of mm is preferred from the viewpoints of adherence and growth of microorganisms, retention and fluidity, but the carrier is not limited thereto as long as it is a carrier to which microorganisms adhere and grow. Further, the filling amount of the biological carrier 7 is preferably 20 to 60% based on the liquid volume in the treatment tank 2.

Reference numeral 3 denotes a sedimentation tank, which is a sludge separation means for solid-liquid separation of a mixed liquid of the sludge after the biological treatment and the treated water. As the sludge separation means, a membrane separation device other than the sedimentation tank 3 is used. Alternatively, as shown in FIG. 3, a means combining a settling tank 3 with a sludge concentrating device 6 such as a membrane separation device, a centrifugal separation device, or a filtration device may be used. Numeral 4 denotes a sludge treatment tank which performs aerobic biological treatment of the separated sludge under a higher temperature condition than that of the fluidized bed biological treatment tank 2 and efficiently kills and decomposes the microorganisms to convert the organic matter into low-molecular-weight substances, and solubilizes the sludge. .

In FIG. 2, reference numeral 5 denotes a flowable biological carrier 7.
Is filled, aerobic microorganisms adhere to and grow on the biological carrier 7 and float, and the sludge biologically treated in the sludge treatment tank 4 is aerated with an oxygen-containing gas, whereby the sludge is subjected to the biological action of the aerobic microorganisms. It is a fluidized bed type sludge re-aeration treatment tank (hereinafter simply referred to as a re-aeration tank) for oxidatively decomposing organic substances in water. In addition, as the biological carrier 7 to be filled, the carrier used in the treatment tank 2 can be used. The structure of the re-aeration tank 5 is preferably substantially the same except that it is smaller than the processing tank 2, but is not limited thereto. In FIGS. 1 and 2, the treatment tank 2 and the re-aeration tank 5 are formed as fluidized bed treatment tanks for fluidizing and treating the biological carrier, but the biological carrier is fixed in the treatment tank. It may be formed as a fixed-bed processing tank provided.

A method for treating raw water, which is an organic waste water, using the apparatus having the above-described configuration will be described in detail below. In the apparatus shown in FIG. 1, raw water is supplied from a raw water supply pipe a to a regulating tank 1 and temporarily stored therein. It is supplied to the processing tank 2. The raw water supplied to the treatment tank 2 is efficiently oxidatively decomposed by organic matter in the raw water by the biological action of aerobic microorganisms (hereinafter referred to as sludge) attached to and propagated on the flowing biological carrier 7. The processing temperature is preferably from 10 to 50C.

The mixed liquid after the treatment in which the organic matter is decomposed and the multiplied sludge is mixed is introduced into the sedimentation tank 3 from the mixed liquid discharge pipe c, and the sludge is settled and separated. It is discharged out of the system from the discharge pipe d. Further, a part of the separated sludge is circulated from the circulation channel f to the treatment tank 2 as return sludge, and the remaining sludge is supplied to the sludge treatment tank 4 from the sludge discharge channel e.

The sludge supplied to the sludge treatment tank 4 is aerated with an oxygen-containing gas at a higher temperature than the fluidized-bed type biological treatment tank 2 so that microorganisms that form sludge by the biological action of high-temperature aerobic microorganisms are obtained. Is efficiently killed and decomposed into low-molecular-weight organic matter and solubilized. In addition, as processing temperature, 55-75 degreeC, the sludge density | concentration is 1-10 vol%,
The treatment is preferably performed with a residence time of 10 to 50 hours. The sludge solubilized by the high-temperature biological treatment is circulated from the solubilized sludge circulation channel g to the treatment tank 2, and the solubilized organic matter is biologically oxidatively decomposed together with the organic matter in the raw water.

In the circulation of the sludge in FIG. 2, part of the sludge separated in the sedimentation tank 3 is circulated from the circulation channel f to the re-aeration tank 5 as returned sludge, and the remaining sludge is removed from the sludge extraction channel e. From the sludge treatment tank 4. The sludge solubilized by the high-temperature biological treatment in the sludge treatment tank 4 is supplied to the re-aeration tank 5 from the solubilized sludge supply channel j, and the solubilized organic matter is deposited on the flowing biological carrier 7 to remove the sludge. Biologically oxidatively decomposes biologically. The re-aerated sludge is circulated to the treatment tank 2 from the re-aerated sludge circulation channel h. In FIG. 3, a part of the separated sludge is circulated from the circulation channel f to the treatment tank 2 as returned sludge, and the remaining sludge is passed through the sludge discharge channel e from the sludge concentration device 6.
And further concentrated. The concentrated sludge is
The sludge supplied from the concentrated sludge supply passage k to the sludge treatment tank 4 and solubilized by the high-temperature biological treatment in the sludge treatment tank 4 is circulated from the solubilized sludge circulation passage m to the treatment tank 2 and solubilized. Organic matter is biologically oxidatively decomposed together with organic matter in raw water.

As described above, large microorganisms, such as the viper beetle and the rotifer, which are the main microorganisms that prey on the organic matter in the wastewater and the organic matter in the solubilized sludge and biologically oxidatively decompose, adhere to the surface of the carrier efficiently. Proliferate, they are held in the processing tank 2 or the re-aeration tank 5, and organic matter is efficiently decomposed. Therefore, the processing efficiency of organic substances is high, and the size of the processing tank and the processing time can be reduced. Further, in the sludge treatment tank 4, suspended microorganisms are efficiently killed and decomposed, solubilized, and the solubilized sludge is circulated to the biological treatment tank. It is possible to reduce the volume of generated gas or to reduce it to zero.

[0027]

According to the present invention, highly efficient treatment of organic wastewater can be performed, operating costs and equipment costs can be reduced, and the amount of sludge generated as a whole can be reduced or eliminated. This is a wastewater treatment device that can be used.

[Brief description of the drawings]

FIG. 1 is a system diagram of a wastewater treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a system diagram of a wastewater treatment apparatus according to another embodiment of the present invention.

FIG. 3 is a system diagram of a wastewater treatment apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 1: Conditioning tank 2: Fluidized bed biological treatment tank 3: Sedimentation tank 4: Sludge treatment tank 5: Fluidized bed sludge re-aeration treatment tank 6: Sludge concentrator 7: Biological carrier

Claims (4)

[Claims] A wastewater treatment apparatus for aerobic biological treatment of organic matter in an organic wastewater, a biological treatment tank filled with a biological carrier for aerobic biological treatment of organic matter in the organic wastewater, and a sludge after the biological treatment. Sludge separation means for solid-liquid separation of the mixed liquid with treated water, a circulation channel for circulating part of the separated sludge to the biological treatment tank, and aerobic biological treatment of the remaining separated sludge at a higher temperature than the biological treatment tank A wastewater treatment apparatus, comprising: a sludge treatment tank that performs the treatment; and a high-temperature treatment sludge circulation channel that circulates the sludge after the high-temperature treatment in the biological treatment tank. 2. A wastewater treatment apparatus for aerobic biological treatment of organic matter in an organic wastewater, a biological treatment tank for aerobic biological treatment of organic matter in the organic wastewater, and a mixture of sludge and treated water after the biological treatment. Sludge separation means for solid-liquid separation of liquid, sludge re-aeration tank filled with biological carrier for a part of separated sludge with aerobic biological treatment, and aerobic biological treatment of remaining separated sludge at higher temperature than biological treatment tank A sludge treatment tank, a high-temperature treatment sludge supply passage for supplying sludge after the high-temperature biological treatment to the sludge re-aeration tank, and a re-aeration sludge circulation passage for circulating the sludge after the sludge re-aeration treatment to the biological treatment tank. A wastewater treatment device characterized by being provided. 3. The wastewater treatment apparatus according to claim 1, wherein the biological treatment tank and / or the sludge re-aeration tank is a fluidized bed treatment tank filled with a biological carrier so as to be able to flow. 4. A sludge separating means comprising a combination of a settling tank and a sludge concentrating device.
A wastewater treatment device according to item 1.