JP3952272B2 - Aerobic treatment tank and sewage purification tank having particle agglomeration chamber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aerobic treatment tank that can be suitably incorporated in a sewage septic tank that purifies human waste, other domestic wastewater, and the combined sewage (also simply referred to as sewage), and a sewage septic tank that incorporates the aerobic treatment tank. Is.
[0002]
[Prior art]
The present inventors, from the upstream, anaerobic filter bed tank first chamber, anaerobic filter bed tank second chamber, aerobic filter bed tank (consisting of an upper compartment biological reaction bed and a lower compartment filter bed), A sewage purification tank equipped with a treatment water tank and a disinfection tank was developed (Japanese Patent No. 2904102). Further, as an improvement or modification of the sewage septic tank, a sewage septic tank having an aerobic treatment tank in which a biological reaction bed and a filtration bed are juxtaposed with a partition wall therebetween is proposed (Japanese Patent Laid-Open No. 2001-246390).
[0003]
On the other hand, JP-A-2001-79580 discloses a sewage purification tank (FIG. 6) composed of a contaminant removal tank A, an anaerobic filter bed tank B, a biological filtration tank C, a treated water tank D, and a disinfection tank E from the upstream. In the biological filtration tank C disclosed, the aerobic treatment zone M is formed in the middle, the filtration treatment zone N is formed in the lower part, and the upper side of the aerobic treatment zone M is “electrochemically contains metal ions. A dephosphorization device P having a metal electrode to be eluted is arranged. Phosphate ions contained in the sewage react with electrochemically eluted metal ions to produce insoluble matter, and the fluid carrier in the aerobic treatment zone M collides with or rubs the metal electrode. Remove the biological film attached to the metal electrode and the non-moving film on the electrode surface.
[0004]
[Problems to be solved by the invention]
The present invention was completed in the process of further improving the sewage septic tank of the above-mentioned Patent No. 2904102, and the object thereof is an aerobic septic tank capable of obtaining better treated water quality, and sewage incorporating the same. It is to provide a septic tank.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration. That is, the present invention is an aerobic treatment tank 1 in which an aerobic biological reaction chamber 2, a particle agglomeration chamber 3, and a filtration chamber 4 are partitioned, and these are juxtaposed in the order of flow.
Here, the particle aggregation chamber 3 is preferably provided with an electrode pair for eluting metal ions.
[0006]
The present invention is also a sewage purification tank incorporating the aerobic treatment tank, that is, a sewage purification tank including the anaerobic treatment tank, the aerobic treatment tank 1, and the disinfection tank 23 in order from the upstream.
Here, the anaerobic treatment tank may be an anaerobic filter bed tank (first chamber, second chamber) provided with a filter bed. The first solid-liquid separation chamber having no filter bed and the second solid-liquid separation chamber arranged in the upper part of the first solid-liquid separation chamber, the bottom of the second solid-liquid separation chamber May be an anaerobic treatment tank that is open and communicated with the first solid-liquid separation chamber.
[0007]
[Action]
In the biological reaction chamber 2 in which the biological carrier (also referred to as a microorganism adhering material, a carrier, a contact material, etc.) is in a fluid state due to the air diffused from the air diffuser 5, the solid particles originally contained in the influent (sewage) In addition, there are suspended particles such as biological sludge (SS) generated by the decomposition and conversion of organic matter. Although these suspended particles have a property of agglomerating to form flocs, they are finely divided by the influence of air bubbles discharged from the air diffusing tube 5 and the collision of the fluid carrier to form so-called pin flocs (fine particles). If the pin flock remains as it is, it is difficult to capture in the subsequent filtration chamber 4 and easily leaks outside. Therefore, the liquid exiting from the biological reaction chamber 2 is once guided to the particle agglomeration chamber 3, and pin flocs are agglomerated to form large particles, which are captured by the subsequent filtration chamber 4.
[0008]
In order to coagulate and grow pin floc, first, the advection liquid from the biological reaction chamber 2 is gently guided to the particle aggregation chamber 3. Therefore, metal ions are eluted from one side of the electrode pair 9 containing metal by electrolysis or electrolysis by applying a voltage to form a hardly soluble metal hydroxide. At this time, the surface potential of the pin floc that has advected also changes, causing aggregation and growth. When phosphate ions are present in the advection liquid, metal ions and phosphate ions react to form insoluble phosphate at the same time. Thus, since the liquid containing a comparatively big aggregate flows into the following filtration chamber 4, the capture | acquisition property of SS in the filtration bed 4a improves, and the water quality (transparency) of treated water improves.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described more specifically with reference to the accompanying drawings.
FIG. 1 shows an aerobic treatment tank according to an example of the present invention, in which an (aerobic) biological reaction chamber 2, a particle aggregation chamber 3, and a filtration chamber 4 are arranged in this order from the upstream side.
[0010]
First, the particle aggregation chamber 3 will be described. (Aerobic) The particle agglomeration chamber 3 is arranged in a part of the biological reaction chamber 2 so as to be adjacent to the filtration chamber 4, that is, on the wall side opposite to the sewage inflow port 7. Is provided with water-permeable members (slits, meshes, etc.) that allow liquids to pass but not biological carriers. The particle agglomeration chamber 3 can be disposed in one corner of the biological reaction chamber 2 at a corner far from the sewage inlet 7 or in the central portion of the biological reaction chamber 2.
[0011]
In the particle agglomeration chamber 3, in order to supply metal ions for aggregating the floating particles advancing from the biological reaction chamber 2, an electrode pair 9 containing metal is arranged and the metal ions are eluted by an electrochemical reaction or the like.
[0012]
As a method for supplying metal ions, as described below, there are methods such as electrochemical reaction and electrolysis by voltage application.
(Electrochemical reaction)
In this method, a metal located above the ionization row and a metal located below the ionization row are joined at one end to form an electrode pair, which is immersed in a solution to elute the metal ions. For example, aluminum and zinc, aluminum and iron, aluminum and nickel, aluminum and copper, aluminum and silver, zinc and iron, zinc and nickel, zinc and copper, zinc and silver, iron and nickel, iron and copper, iron and silver, etc. Electrode pair. Each metal material may be alloyed or plated. These electrode pairs elute the upper metal in the ionization column in the liquid.
[0013]
FIG. 2 shows an example in which an iron plate 9a having a large ionization row and a silver-plated copper plate 9b having a smaller ionization row are combined. When the electrode pair is immersed in the liquid, iron ions are eluted from the iron plate 9a side having a large ionization row. The eluted iron ions form hydroxides. At this time, the suspended particles that have advected also aggregate due to the change in surface potential.
[0014]
(Electrolysis by applying voltage)
This is a method in which a pair of electrodes made of different kinds of metal materials or the same kind of metal materials is arranged, and a voltage is applied to cause electrolysis to elute metal ions from the anode side. Examples of the electrode include an electrode pair made of the same metal material such as zinc and zinc, iron and iron, aluminum and aluminum, and an electrode pair made of different metals such as zinc and iron, iron and aluminum. Further, a conductor such as carbon can be used on the cathode side.
[0015]
FIG. 3 shows an example in which an anode iron plate 9c and a cathode iron plate 9d are combined. When a voltage is applied, iron ions are eluted from the iron plate 9c side of the anode. The eluted iron ions form hydroxides as in the case of the electrochemical reaction, and agglomerated floating particles are agglomerated.
[0016]
In order to effectively bring the particles into contact with each other, a protrusion may be provided on the partition wall, or a filler such as a honeycomb core that plays the role of a static mixer may be disposed in the particle aggregation chamber (not shown).
[0017]
In the biological reaction chamber 2 upstream of the particle agglomeration chamber 3, a diffusion member (aeration tube) 5 is arranged at the bottom in order to flow and agitate the biological carrier and the liquid in the tank, and supply oxygen together. Air is sent from the blower 6 to this. The air diffuser 5 may have a single letter shape in a plan view, a circular or triangular loop shape, an eye shape, or a square loop shape.
[0018]
The biological reaction chamber 2 is filled with a biological carrier to such an extent that it can flow with aeration, that is, 30 to 60% (preferably 35 to 55%) by volume. Due to the aeration from the air diffuser 5, the liquid in the tank and the biological carrier flow and come into contact with each other, and further, the decomposition of the organic matter proceeds in a favorable y direction due to the uniform diffusion of dissolved oxygen.
[0019]
The biological carrier is preferably one that floats and flows in the liquid with stirring force by aeration. The specific gravity is about 0.9 to 1.1. As the shape of the biological carrier, various shapes such as a hollow cylindrical shape, a spherical shape, a cylindrical shape, a cubic shape, a net-like cylindrical shape, a loofah shape, a skeletal shape, and the like can be used. Each length is preferably about 10 mm (about 5 to 20 mm). A larger specific surface area is more preferable. As the base material, a synthetic resin such as polypropylene, polyethylene, polyvinyl chloride, polyvinyl alcohol, and polyvinyl formal is preferably used.
[0020]
In the filtration chamber 4 downstream of the particle aggregation chamber 3, a filter bed 4a filled with a filter medium is disposed, and an air diffuser 11 connected to the blower 6 is disposed below or below the filter bed 4a. During normal processing, air is not discharged from the diffusing tube 11, and suspended particles such as SS are mainly filtered in a stationary state. If the operation is continued, the filter bed 4a is clogged by the captured SS or the like, so sometimes (once or several times a day) it diffuses from the air diffuser 11, and the captured SS is peeled off to remove the filter bed 4a. Backwash. At the same time, the liquid in the tank is pulled out from the bottom of the filtration chamber 4 using an air lift pump or the like (see FIG. 5B). In the filtration chamber 4, in addition to the capture of SS, aerobic biodegradation further proceeds due to dissolved oxygen carried over from the biological reaction chamber 2.
[0021]
FIG. 4 shows an aerobic treatment tank according to another embodiment of the present invention. In this configuration, the (aerobic) biological reaction chamber 2, the particle aggregation chamber 3, and the filtration chamber 4 are juxtaposed side by side in order from the upstream side where the sewage flows. Other configurations are the same as those shown in FIG. In FIG. 1 and FIG. 4, the biological reaction chamber 2, the particle aggregation chamber 3, and the filtration chamber 4 have a quadrangular shape in plan view, but these may have a circular shape (particularly in the particle aggregation chamber 3). .
[0022]
FIG. 5 is an example of a sewage purification tank incorporating the aerobic treatment tank. The sewage purification tank 20 is, in order from the upstream where sewage flows in, a first solid-liquid separation chamber 21 serving as a first anaerobic treatment tank, a second solid-liquid separation chamber 22 serving as a second anaerobic treatment tank, (aerobic). The biological reaction chamber 2, the particle aggregation chamber 3, the filtration chamber 4, and the disinfection tank 23 are configured.
[0023]
The first solid-liquid separation chamber 21 has a sewage inlet 25, and the first solid-liquid separation chamber 21 and the second solid-liquid separation chamber 22 are connected by an opening 26 at the bottom of the second solid-liquid separation chamber 22. . The first solid-liquid separation chamber 21 and the second solid-liquid separation chamber 22 have a flow rate adjusting unit 27 (minimum water level L.L) for averaging the sewage inflow fluctuation and transferring it to the biological reaction chamber 2 and the subsequent stages. W.L to the highest water level H.W.L). The second solid-liquid separation chamber 22 is provided with a transfer air lift pump 28 for quantitatively transferring the liquid in the tank to the biological reaction chamber 2, and the suction port 29 has a minimum water level L.P. W. L is provided.
In addition, instead of the first solid-liquid separation chamber 21 and the second solid-liquid separation chamber 22, an anaerobic filter bed tank having a filter bed filled with a biological carrier may be used, and there is only one anaerobic treatment tank. There may also be two rooms. Further, the flow rate adjusting function can be removed.
[0024]
In the particle aggregation chamber 3, an electrode pair using an electrochemical reaction is arranged, and a part of the advection water from the (aerobic) biological reaction chamber 2 is circulated to the first solid-liquid separation chamber 21. A circulation air lift pump 30 and a cleaning drainage pump 31 for extracting the cleaning wastewater from the filtration chamber 4 and transferring it to the first solid-liquid separation chamber 21 are arranged. The circulation air lift pump 30 and the cleaning / drainage extraction pump 31 may be a transfer pump such as an electric pump. Further, the circulation air lift pump 30 may not be arranged.
[0025]
The filtration chamber 4 is also provided with a washing drainage pump 31 for drawing out the washing drainage when the filtration bed 4a is backwashed. Air is supplied from the blower 6 to the transfer air lift pump 28, the circulation air lift pump 30, and the cleaning drainage extraction pump 31. In the filtration chamber 4, the flow direction of the liquid is a downward flow. This flow direction can also be an upward flow.
[0026]
Next, the sewage treatment method in the sewage septic tank 20 will be described. The inflowing sewage enters the first solid-liquid separation chamber 21 from the sewage inlet 25 as indicated by solid arrows, and solid-liquid separation and anaerobic biological treatment are performed. The advection liquid that has passed through here enters the second solid-liquid separation chamber 22, and further undergoes solid-liquid separation and anaerobic biological treatment. The liquid is quantitatively transferred to the biological reaction chamber 2 by the transfer air lift pump 28 while the flow rate fluctuation of the influent wastewater is reduced in the first solid-liquid separation chamber 21 and the second solid-liquid separation chamber 22.
[0027]
The liquid flowing into the biological reaction chamber 2 comes into contact with the air discharged from the diffuser tube 5 and the flowing biological carrier, and aerobic biodegradation proceeds. A part of the decomposed organic matter is converted into a microorganism, and a part of the microorganism adheres to the biological carrier or floats as SS (including pin floc) in the liquid. The SS mixed liquid flows into the particle agglomeration chamber 3 from a liquid inlet 8 provided at the lower part.
[0028]
In the particle agglomeration chamber 3, the pin flocs contained in the influent are agglomerated and grown by the metal ions eluted from the arranged metal pairs. When phosphate ions are contained in the advection liquid, the eluted metal ions react with phosphate ions to form insoluble phosphate. The insoluble phosphate aggregates and grows together with the pin floc. In addition, a circulating air lift pump 30 is disposed in the particle agglomeration chamber 3, and a part of the liquid is continuously or intermittently returned to the first solid-liquid separation chamber 21 where SS is separated.
[0029]
The remaining liquid enters the filtration chamber 4 from the outlet 33, where SS is captured and removed by the filler (filter medium) of the filtration bed 4a, and the biological treatment continues. The filtrate is discharged as treated water from the outlet 34 through the disinfection tank 23.
[0030]
The filter medium is washed in the filtration chamber 4 as follows. First, air is discharged from the air diffuser 11, and the filter bed 4a is bubbled to separate the SS. At this time, the cleaning drainage pump 31 is operated, and the cleaning drainage is extracted from the bottom of the filtration chamber 4 and returned to the first solid-liquid separation chamber 21. At this time, it is preferable to draw out the entire amount of the washing waste water. Cleaning is completed when the drainage of the cleaning wastewater is completed. This washing is preferably performed when the water level in the first solid-liquid separation chamber 21 is near the lowest water level (LWL) (that is, when there is no inflow of sewage).
[0031]
【The invention's effect】
According to the aerobic treatment tank or the sewage septic tank of the present invention, the fine particles pin-flocculated in the fluidized (aerobic) biological reaction chamber are agglomerated and grown in the particle agglomeration chamber to form larger particles. Therefore, it is possible to improve the SS capturing performance in the subsequent filtration chamber. Therefore, high-quality treated water with high transparency can be obtained. In addition, the soluble phosphoric acid content contained in the wastewater can also be removed as insoluble particles.
[Brief description of the drawings]
1A and 1B are aerobic treatment tanks according to an embodiment of the present invention, in which FIG. 1A is a schematic plan view, and FIG. 1B is a schematic cross-sectional view taken along the AA plane in FIG.
FIG. 2 is a schematic cross-sectional view of a particle aggregation chamber in which electrode pairs by electrochemical reaction are arranged.
FIG. 3 is a schematic cross-sectional view of a particle aggregation chamber in which electrode pairs are arranged by electrolysis with voltage application.
4A and 4B are aerobic treatment tanks according to another embodiment of the present invention, in which FIG. 4A is a schematic plan view, and FIG. 4B is a schematic cross-sectional view taken along the plane BB of FIG.
5A is a schematic plan view, and FIG. 5B is a schematic cross-sectional view of the CC plane of FIG. 6A. FIG. 6 is a schematic view of a conventional sewage septic tank according to an embodiment of the present invention. FIG.
[Explanation of symbols]
1: aerobic treatment tank 2: (aerobic) biological reaction chamber 2a: biological reaction bed 3: particle agglomeration chamber 4: filtration chamber 4a: filtration bed 5: diffuser member (diffuser tube) 6: blower 7: sewage flow Inlet 8: Liquid inlet part (water-permeable member)
9, 9a, 9b, 9c, 9d: Electrode pair (metal plate)
11: Air diffuser (air diffuser)
20: Wastewater purification tank 21: Anaerobic treatment tank first chamber (first solid-liquid separation chamber)
22: Anaerobic treatment tank second chamber (second solid-liquid separation chamber)
23: Disinfection tank 24: Disinfection tank 26: Opening part 27: Flow rate adjustment part 28: Air lift pump for transfer 29: Suction port 30: Air lift pump for circulation 31: Washing drain pump 33: Outlet 34: Outlet A: Contamination Waste removal tank B: Anaerobic filter bed tank C: Biological filtration tank D: Treated water tank E: Disinfection tank M: Aerobic treatment zone N: Filtration treatment zone P: Dephosphorization device

Claims (2)

A biological reaction chamber, a particle agglomeration chamber, and a filtration chamber are each partitioned, and the biological reaction chamber has an aeration tube and a biological carrier that can flow by aeration from the aeration tube, and the particle aggregation chamber An aerobic treatment tank having an electrode pair for eluting metal ions . A sewage purification tank comprising an anaerobic treatment tank, an aerobic treatment tank according to claim 1 and a disinfection tank in order from the upstream .

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