JP2016185523A - Anaerobic treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote growth of microorganisms on a carrier and further reduce time needed for starting up a device in an anaerobic treatment device and an anaerobic treatment method for conducting an anaerobic treatment by anaerobic microorganisms with using the carrier to which microorganisms adheres.SOLUTION: To dissolve the above described problem, there is provided an anaerobic treatment device having an anaerobic treatment part for an anaerobic treatment of water to be treated and a coagulant adding means for adding a coagulant, where the coagulant adding means is arranged on a supply line for supplying water to be treated to a lower part of the anaerobic treatment part or a circulation line for returning treated water exhausted from the anaerobic treatment part to the lower part of the anaerobic treatment part. Because the coagulant with high concentration can be added into mixture of the carrier and microorganisms, the microorganisms aggregate on a surface or inside of the carrier and adhesion of the microorganisms to the carrier is promoted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anaerobic treatment apparatus for biologically treating organic wastewater such as wastewater from a food factory or the like with anaerobic microorganisms.

  Biological treatment with anaerobic microorganisms is known as a method of treating wastewater from food factories and organic wastewater such as sewage. Biological treatment with anaerobic microorganisms is widely used as an industrial wastewater treatment method because it can recover methane gas. Among them, the UASB (Upflow Anaerobic Sludge Blanket) method, which forms granules with good sedimentation and passes organic wastewater in an upward flow for high-load high-speed treatment, It has been developed as a method for treating medium to high concentration wastewater. As an extension of the UASB method, the EGSB (Expanded Granule Sludge Blanket) method, which uses a high-height reaction tank to pass water at a higher flow rate and performs anaerobic treatment with a high load, has also been put to practical use. Yes.

  A method using a fixed bed carrier or a fluidized bed carrier is also known. A fixed bed carrier uses a microorganism that grows on the surface of a support bed that holds a biofilm fixed inside the reaction vessel, and a fluid bed carrier contains a carrier whose specific gravity and size are adjusted inside the reaction vessel. The treatment is performed by allowing the organism to grow on the carrier by flowing.

  However, in the case where a carrier is used regardless of whether it is a fixed bed carrier or a fluidized bed carrier, there is a drawback that it takes time for the growth of microorganisms on the carrier, and as a result, it takes a lot of time to start up the apparatus. Therefore, a method for promoting the growth of microorganisms on a carrier has been studied.

  For example, Patent Document 1 discloses that when starting up a reaction tank holding a carrier, methane bacteria aggregates having an average particle size of 10 μm or more and 450 μm or less are added as seed sludge in a range of 1 to 900 g per 1 L of the carrier. A method for greatly reducing the time required for starting up the apparatus is described.

JP, 2014-100680, A

  The subject of this invention is providing the anaerobic processing apparatus and the anaerobic processing method which can accelerate | stimulate the proliferation of the microorganisms on a support | carrier in order to further shorten the time required for starting of an apparatus.

As a result of intensive studies on the above problems, the present inventor has found that the addition of a flocculant promotes the adhesion between anaerobic microorganisms and the carrier and increases the growth rate of the microorganisms on the carrier. Was completed.
Specifically, it is the following anaerobic treatment apparatus or anaerobic treatment method.

  The anaerobic treatment apparatus of the present invention for solving the above problems is an anaerobic treatment apparatus that anaerobically treats water to be treated using a carrier, an anaerobic treatment unit that anaerobically treats the water to be treated, and a flocculant. A flocculant addition means to be added, wherein the flocculant addition means supplies the treated water to the lower part of the anaerobic treatment section, or the treated water discharged from the anaerobic treatment section is anaerobic The anaerobic treatment device is provided in a circulation line returning to a lower portion of the processing unit.

  According to this anaerobic treatment apparatus, the flocculant aggregates the anaerobic microorganisms on the surface or inside of the carrier, so that the adhesion between the microorganisms and the carrier is promoted, and the growth rate of the microorganisms on the carrier can be increased.

  Moreover, in this anaerobic processing apparatus, a coagulant | flocculant is added to the supply line or circulation line connected with the lower part of the anaerobic processing part. Therefore, the flocculant flows in from the supply line or the circulation line below the anaerobic treatment unit in a high concentration state and is supplied so as to diffuse inside the anaerobic treatment unit. On the other hand, since the carrier settles at the lower part of the anaerobic treatment part and accumulates at a position where the flocculant flows at a high concentration, the high concentration of the flocculant is mixed with the carrier to further promote the adhesion between the microorganism and the carrier. it can.

Furthermore, the circulation line is formed as a circulation path for returning the treated water to the lower part of the anaerobic treatment section by being connected to the supply line, and the flocculant adding means is provided in this circulation path.
According to this configuration, since the circulation path is formed using a part of the circulation line and the supply line, the apparatus can be simplified.

Furthermore, the anaerobic treatment unit has a shape having a bottom surface of an inverted truncated cone at the bottom of the cylinder, and the supply line or the circulation line is connected to the top of the inverted truncated cone. Have.
According to this configuration, since all the carriers flow in order, a carrier that stays and does not come into contact with the flocculant is not generated. Therefore, microorganisms can be uniformly attached on all the carriers.

  The anaerobic treatment method of the present invention for solving the above problems is an anaerobic treatment method for anaerobic treatment of water to be treated using a carrier, an anaerobic treatment of the water to be treated in an anaerobic treatment part, and aggregation And the flocculant is a supply line for supplying the water to be treated to the lower part of the anaerobic treatment unit, or the treated water discharged from the anaerobic treatment unit. The anaerobic treatment method is characterized in that the anaerobic treatment method is added to the circulation line returning to the lower part of the gas.

According to this anaerobic treatment method, like the anaerobic treatment apparatus of the present invention, the flocculant promotes the adhesion between the anaerobic microorganisms and the carrier, so that the growth rate of the microorganisms on the carrier can be increased.
Further, since the flocculant is added to the supply line or circulation line connected to the lower part of the anaerobic treatment section, the flocculant having a high concentration is mixed with the carrier, and the adhesion between the organism and the carrier is further promoted.

  According to the anaerobic treatment apparatus and the anaerobic treatment method of the present invention, adhesion of anaerobic microorganisms on the carrier is promoted, so that the growth rate of microorganisms on the carrier is increased and the time required for starting up the device is shortened. Can do.

It is a schematic explanatory drawing which shows the structure of the anaerobic processing apparatus 1a of the 1st embodiment of this invention. It is a schematic explanatory drawing which shows the structure of the anaerobic processing apparatus 1b of the 2nd embodiment of this invention. It is a schematic explanatory drawing which shows the structure of the anaerobic processing apparatus 1c of the 3rd embodiment of this invention.

  Below, the anaerobic processing apparatus and the anaerobic processing method of this invention are demonstrated.

The anaerobic treatment apparatus of the present invention is an apparatus that anaerobically treats water to be treated using a carrier to which microorganisms adhere, and discharges it as treated water.
Here, the water to be treated of the present invention includes organic wastewater containing organic matter such as industrial wastewater, domestic wastewater, and sewage discharged from food factories.

(Anaerobic treatment)
As long as the anaerobic treatment is a biological treatment under anaerobic conditions, any microorganism may be used. Examples include methane-producing bacteria that decompose organic matter to produce methane, denitrifying bacteria that reduce nitric acid and nitrous acid to nitrogen, sulfate-reducing bacteria that reduce sulfuric acid, and hydrogen-producing bacteria that reduce hydrogen ions. It is done. Since methane can be reused as fuel, biological treatment with methanogenic bacteria is preferable.

(Carrier)
The carrier may be any substance as long as it is a solid to which microorganisms adhere. For example, silica sand, ceramics, activated carbon, polymer, clay, incinerated ash, blast furnace granulated slag and the like can be mentioned. The carrier can be used as a fixed bed fixed inside the anaerobic treatment section or a fluidized bed flowing inside. It is preferable to use a fluidized bed in order to evenly adhere microorganisms to the carrier.
When using a fluidized bed, it is preferable to use a carrier having a specific gravity greater than that of water to be treated from the viewpoint of excellent sedimentation.

  The shape of the carrier may be any shape, and examples thereof include a spherical shape, a pellet shape, a honeycomb shape, a small cylindrical shape, a tube shape, and a cubic shape. From the viewpoint of easy attachment of microorganisms, it is preferable to use a carrier having a high porosity such as a sponge.

  The carrier used for the fluidized bed is a granular carrier having a diameter of 1 to 5 mm, and considering a sedimentation property and adhesion, a spherical shape having a diameter of 3 to 4 mm is preferable. In addition, the diameter of a granular support | carrier is the average value which measured the largest diameter about 100 granular materials. The maximum diameter is measured using an electron microscope.

The amount of carrier used in the fluidized bed is 10 to 50%, preferably 10 to 30%, based on the volume of water to be treated in the anaerobic treatment section. In the case of less than 10%, since the carrier to which microorganisms adhere is small, the anaerobic treatment speed of the water to be treated is lowered. On the other hand, when it exceeds 50%, the fluid state is deteriorated, and the adhesion of microorganisms to the carrier may be uneven.
In addition, as a method of measuring the capacity of the carrier, for example, a method of calculating the amount of the increased amount of treated water as the capacity of the carrier, by introducing the carrier into the treated water previously introduced into the anaerobic treatment unit, A method of calculating the volume from the bulk density of the carrier may be used.

(Flocculant)
In the anaerobic treatment apparatus of the present invention, a flocculant is used when attaching the carrier and the microorganism. The coagulant is supplied while the carrier and the microorganism are mixed, and the microorganism is aggregated on the surface or inside of the carrier to promote the adhesion of the microorganism on the carrier.

  As the flocculant, any substance may be used as long as it can agglutinate microorganisms. Examples thereof include cationic, nonionic, anionic and amphoteric flocculants, which are appropriately selected according to the processing conditions. Since microorganisms are often negatively charged, it is preferable to use a cationic flocculant. More preferred is a method in which a cationic flocculant and a nonionic flocculant are used in combination, and particularly preferred is a method in which a nonionic flocculant is applied after the cationic flocculant is applied. By using a nonionic flocculant in combination, the flocculation effect is enhanced and adhesion of microorganisms to the carrier can be further promoted.

Examples of cationic flocculants include inorganic flocculants such as polyferric sulfate, ferric chloride, polysilica iron, polyaluminum chloride, polyaminoalkyl methacrylate, polyethyleneimine, polydiallylammonium halide, chitosan, urea-formalin. Examples thereof include a polymer flocculant such as a resin. From the viewpoint of excellent cohesiveness, it is preferable to use a polymer flocculant.
Examples of nonionic flocculants include polyacrylamide and polyethylene oxide.
Examples of the anionic flocculant include sodium polyacrylate, polyacrylamide partial hydrolyzate, partially sulfomethylated polyacrylamide, poly (2-acrylamide) -2-methylpropane sulfate, and the like.
Examples of amphoteric flocculants include copolymers of acrylamide, aminoalkyl methacrylate and sodium acrylate.

  The amount of the flocculant used is 0.1% by mass or more, preferably 0.1 to 10% by mass, particularly preferably 0%, based on the solid content of the seed sludge blended as the raw material of the microorganism. 0.1 to 1% by mass. When the amount is less than 0.1% by mass, a sufficient aggregation effect cannot be obtained. Moreover, even if it uses exceeding 10 mass%, the aggregation effect does not become so high.

(Seed sludge)
The microorganisms mixed with the carrier may use anaerobic sludge obtained by the above anaerobic treatment or granular sludge as seed sludge.
The compounding quantity of seed sludge is 1000-10000 mg / L as solid content, Preferably, it is 3000-5000 mg / L. In the case of less than 1000 mg / L, since the amount of microorganisms adhering to the carrier is small, the growth rate of microorganisms on the carrier is slow. On the other hand, even if it exceeds 10,000 mg / L, the effect of the present invention that adhesion of anaerobic microorganisms on the carrier is promoted hardly increases.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 is a schematic explanatory view showing an anaerobic treatment apparatus 1a according to a first embodiment of the present invention.
The anaerobic treatment apparatus 1a of the first embodiment of the present invention includes an anaerobic treatment unit 2 that is subjected to biological treatment with anaerobic microorganisms, a supply line L1 that supplies treated water W0 to the bottom surface of the anaerobic treatment unit 2, and treated water. A flocculant is added to the circulation line L2 and the circulation line L2, which are connected to the discharge line L3 and the supply line L1 for discharging W1, and form a circulation path R for returning a part of the treated water to the bottom surface of the anaerobic treatment unit 2. Flocculant addition means 3 is provided.
A granular carrier C is held inside the anaerobic treatment unit 2.

(Anaerobic treatment part)
The anaerobic treatment part 2 in the first embodiment of the present invention has a cylindrical body with a bottom surface of an inverted truncated cone, and the top of the lower end of the inverted truncated cone is a cylindrical body. Is located at the approximate center of the cross section. A supply line L1 for supplying the water to be treated W0 is connected to the top of the lower end, and the water to be treated W0 flows in from the top and forms an upward flow inside the anaerobic treatment unit 2.

  The granular carrier C flows upward due to the upward flow formed at the approximate center of the anaerobic treatment unit 2, and when it reaches the upper part of the anaerobic treatment unit 2, it diffuses in the circumferential direction and settles around the upward flow. (Refer to the dashed arrows in the drawing.) Then, the settled carrier C flows in an upward flow sequentially. According to this fluid state, no carrier that stays without flowing is generated, and therefore, all the carriers C can be brought into contact with a high concentration flocculant.

  In view of the essence of the present invention in which a high concentration of the flocculant is introduced while the microorganisms and the carrier C are mixed, the shape of the anaerobic treatment unit 2 is formed with an upward flow of the water to be treated WS formed therein. Any shape may be used, and not only a cylindrical body but also an elliptical or polygonal cylindrical body may be used. From the viewpoint of maintaining an even flow state of the carrier C, a cylindrical body is preferable.

  In addition, the shape of the bottom surface is not limited to the inverted truncated cones such as the inverted truncated cone, the inverted truncated elliptical cone, and the inverted truncated polygonal cone that match the shape of the upper cylinder. It may be a flat surface. From the viewpoint of not retaining the carrier C, the shape of the bottom surface is preferably an inverted truncated cone. Particularly preferred is an inverted truncated cone.

  Further, these inverted truncated cones may be inclined cones whose apexes deviate from the center of gravity, but it is preferable that the apexes be provided substantially at the center in order to make the flocculant uniformly contact between the carriers.

(Supply line)
The supply line L <b> 1 is a pipe for supplying the organic waste water that is the treated water W <b> 0 to the anaerobic treatment unit 2, and is connected to the lower end of the bottom surface of the anaerobic treatment unit 2.
In addition, the supply line L1 of the first embodiment is connected to the lower end of the bottom surface of the anaerobic treatment unit 2 in consideration of the good flow state of the carrier C, but the supply line L1 contains the treated water W0. Since it only needs to be connected so as to flow out from the upper drain line L1 after contacting the carrier C, it may be provided below the anaerobic treatment unit 2. More specifically, it may be connected below the upper end of the bed of the carrier C.

(Circulation line)
The circulation line L2 in the first embodiment is a pipe for returning a part of the treated water W1 that has passed through the anaerobic treatment unit 2 to the supply line L1 and configuring the circulation path R. By providing the circulation line, an upward flow can be formed in the anaerobic treatment unit 2 without supplying new water to be treated W0 when the microorganisms are grown on the carrier. Further, even during the treatment of the water to be treated W0, the flow rate of the water to be treated W0 can be assisted to maintain a good fluid state of the carrier C.

In addition, the circulation line L2 does not need to be provided like the 2nd embodiment mentioned later. In that case, when the microorganisms are grown on the carrier, the water to be treated W0 may be circulated.
Moreover, you may comprise the supply line L1 and the circulation line L2 by separate piping like the 3rd embodiment mentioned later. However, it is preferable to form the circulation path by connecting the supply line L1 and the circulation line L2 as in the first embodiment because the apparatus is simplified.

(Coagulant addition means)
A flocculant addition means 3 is connected to the circulation line L2, and the flocculant can be added into the circulation line L2. The added flocculant flows in from the lower end of the bottom surface of the anaerobic treatment unit 2 together with the circulated treated water and comes into contact with the carrier C. With this configuration, a high concentration flocculant can be brought into contact with the carrier C.

  The flocculant addition means 3 may be provided in any of the supply line L1 and the circulation line L2 as long as the flocculant having a high concentration can be brought into contact with the carrier C. When the flocculant addition means 3 is provided in the circulation line L2 or the circulation path R, the supply is performed when adding the flocculant while the microorganisms are growing on the carrier in the circulation flow, such as when adding a plurality of flocculants. Since the flocculant can be added without operating the line L1, the operation becomes easy.

(Drainage line)
The drainage line L3 is provided in the upper part of the anaerobic treatment apparatus 1a, and the treated water W1 flows out of the drainage line L3 due to overflow. The drain line L3 may be branched from the circulation line L2.

(Anaerobic treatment method)
Next, the anaerobic processing method in the anaerobic processing apparatus 1a of the first embodiment will be described. In this anaerobic treatment method, (a) a step of introducing treated water W0 into the anaerobic treatment unit 2, (b) a step of introducing carrier C into the anaerobic treatment unit 2, and (c1) seed sludge into the anaerobic treatment unit 2 (D) a step of circulating the treated water W1 by operating the pump of the circulation line L2, (e1) a step of adding a flocculant to the circulation line L2, and (f1) on the carrier C while circulating the treated water W1. And (g) a step of biologically treating the water to be treated W0 by operating the supply line L1 after the biofilm is formed on the carrier C.
According to this anaerobic treatment method, (f1) it is possible to shorten the time of the step of growing microorganisms on the carrier C while circulating the treated water W1.

[Second Embodiment]
FIG. 2 is a schematic explanatory view showing an anaerobic treatment apparatus 1b according to a second embodiment of the present invention.
In the second embodiment, the circulation line L2 is not provided, and the flocculant adding means 3 is configured to add the flocculant to the supply line L1.
According to this configuration, since the circulation line L2 is not provided, the apparatus can be simplified.

Next, the anaerobic processing method in the anaerobic processing apparatus 1b of the second embodiment will be described. In this anaerobic treatment method, (a) the step of introducing the treated water W0 into the anaerobic treatment unit 2, (b) the step of introducing the carrier C into the anaerobic treatment unit 2, and (c2) introducing seed sludge into the supply line L1. A step, (e2) a step of adding a flocculant to the supply line L1, (f2) a step of growing microorganisms on the carrier C while supplying the water to be treated W0, (g) after a biofilm is formed on the carrier C, A step of biologically treating the water to be treated W0 by operating the supply line L1.
In this anaerobic treatment method, since the introduced seed sludge is discharged from the drainage line L3, the seed sludge needs to be input to the supply line L1 so that the carrier C, the microorganisms, and the flocculant can be brought into contact with each other. is there.

[Third Embodiment]
FIG. 3 is a schematic explanatory view showing an anaerobic treatment apparatus 1c according to a third embodiment of the present invention.
The third embodiment is an example in which the supply line L1 and the circulation line L2 are configured by independent pipes. The flocculant addition means 3 is installed in the circulation line L2, but may be installed in the supply line L1.
The anaerobic treatment method using this apparatus is the same as in the first embodiment.

  The anaerobic treatment apparatus and the anaerobic treatment method of the present invention are used for wastewater treatment for performing anaerobic treatment. For example, it can be suitably used for wastewater treatment of industrial wastewater such as food factories, and organic wastewater discharged from households and the like.

1a, 1b, 1c Anaerobic treatment device, 2 Anaerobic treatment part, 3 Coagulant addition means, P pump, L1 supply line, L2 circulation line, L3 drainage line, C carrier, R circulation path, W0 treated water, W1 treated water

Claims (4)

In an anaerobic treatment apparatus for anaerobically treating treated water using a carrier,
An anaerobic treatment part for anaerobically treating the water to be treated, and a flocculant addition means for adding a flocculant,
The flocculant adding means includes
It is provided in the supply line which supplies the treated water to the lower part of the anaerobic treatment part, or the circulation line which returns the treated water discharged from the anaerobic treatment part to the lower part of the anaerobic treatment part. Anaerobic treatment device. The circulation line is formed as a circulation path for returning the treated water to the lower part of the anaerobic treatment unit by connecting to the supply line,
The anaerobic treatment apparatus according to claim 1, wherein the flocculant addition unit is provided in the circulation path. The anaerobic treatment part has a shape with a bottom surface of an inverted truncated cone at the bottom of the cylinder,
The anaerobic treatment apparatus according to claim 1, wherein the supply line or the circulation line is connected to a top of an inverted truncated cone. In the anaerobic treatment method for anaerobically treating the water to be treated using a carrier,
Anaerobic treatment of the treated water in an anaerobic treatment unit;
Adding a flocculant, and
The flocculant is added to a supply line that supplies the water to be treated to the lower part of the anaerobic treatment part or a circulation line that returns the treated water discharged from the anaerobic treatment part to the lower part of the anaerobic treatment part. An anaerobic treatment method characterized by.

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