JP4307903B2 - Wastewater septic tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biological carrier pressing member suitably used for a sewage septic tank that treats manure discharged from households and the like and other domestic wastewater (also simply referred to as sewage).
[0002]
[Prior art]
FIG. 5 is an example of a sewage septic tank (partial longitudinal sectional view) using a conventional biological carrier pressing member. As shown in the drawing, in the aerobic treatment tank 10 of the sewage purification tank, an upper part, a lower part, and a lower part are provided in order to hold and support a filled biological carrier (also referred to as a biofouling material, a filler, a contact material, or a filter medium). In addition, water passage plates 24, 25, and 26 are arranged in the middle portion, and a biological carrier is filled in a space portion sandwiched between the water passage plates, and a biological cell is attached to and propagated on the biological carrier, and wastewater These organic substances are decomposed and treated aerobically (for example, see Patent Document 1).
[0003]
FIG. 6 shows another example of a sewage septic tank (partial longitudinal sectional view) using a conventional biological carrier pressing member. In this case, a water flow plate 24 is installed above (above) the liquid level WL ( For example, see Patent Document 2).
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-90113
[Patent Document 2]
Japanese Patent Laid-Open No. 2000-210690
[Problems to be solved by the invention]
However, as shown in FIG. 5, in the case where the biological carrier is pressed (upper) and the water flow plate 24 is arranged so as to be immersed in the liquid, the sewage concentration is high in the vicinity of the water flow plate 24 where the sewage flows (upper). Not only the (upper) water flow plate 24 but also biological cells (biofilm) adhere to it, and the holes (or meshes) of the upper water flow plate 24 may be blocked in some cases, and the sewage may be blocked by the blockage. Troubles such as overtopping will occur.
Further, in the case of the other example of FIG. 6, the hole (or mesh) of the water flow plate 24 can be blocked, but sampling at the time of maintenance and inspection, dissolved oxygen amount (BOD), hydrogen ion concentration (pH) in the liquid It is difficult to measure such as.
[0007]
The present invention is intended to solve these problems, and even if a large amount of biological cells (biofilm) adheres to the water flow plate, it is not completely blocked, and therefore the overflow to the next tank is prevented. It is possible to provide an upper water flow plate (that is, a biological carrier pressing member) that can be prevented or that can be easily sampled at the time of maintenance and inspection, and can easily measure BOD, pH, and the like in the liquid.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned problem, the present inventors have made various studies and devised that a part of the upper water flow plate (biological carrier pressing member) is always above the liquid level, thereby providing the upper water flow plate. The present invention has been completed with the idea that blockage of the holes (mesh) of the (biological carrier pressing member) can be prevented.
[0009]
That is, the present invention includes an aerobic treatment tank and a biological carrier pressing member disposed in the aerobic processing tank, and the biological carrier pressing member includes a flat plate-like portion and an upper portion from the flat plate-like portion. And the flat plate-like part is below the liquid level in the tank of the aerobic treatment tank, and a part of the convex part is below the liquid level in the tank during the operation of the aerobic treatment tank. It is a sewage septic tank installed so that it may be on the top.
[0011]
[Action]
In the biological carrier pressing member 1 according to the present invention, the convex portion 3 is formed so as to protrude upward from the flat plate-like portion 2, and a part of the biological carrier pressing member 1 is always immersed from the liquid without being immersed in the liquid. Is also above. Therefore, even if a biological cell (biofilm) adheres to the biological carrier holding member in the liquid and the hole (mesh) of the biological carrier holding member closes, the convex portion 3 above the liquid level has a hole (mesh). There is no blockage.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a perspective view of a biological carrier pressing member 1 according to an example of the present invention. The biological carrier pressing member 1 has convex portions 3 (three locations in FIG. 1) protruding upward, and a part of the convex portions 3 is designed to be always above the liquid level WL in the tank. . In addition, the biological carrier holding member 1 has a number of holes (holes, slits, lattices, or meshes) smaller than the biological carrier filled in the tank so that sewage can freely pass through. It is a structure that does not pass through (the biological carrier is not washed away).
[0013]
Here, the (overall) plan view size of the biological carrier pressing member 1 is set to a size suitable for the plan view size of the aerobic treatment tank 10 in the sewage septic tank. Moreover, it is preferable that the convex part (protrusion part) 3 occupies the area of about 10% or more and 60% or less of the area of the biological carrier pressing member 1 in plan view. The height (L1) of the convex portion 3 varies depending on the size of the sewage septic tank, but when used for a general household septic tank, the height (L1) is approximately 10 to 100 mm exposed from the liquid level (WL).
[0014]
The material of the biological carrier pressing member 1 is usually made of polypropylene, polyethylene, polyvinyl chloride, or the like, and may be made of a metal such as stainless steel, galvanized, or copper. In addition, although the plate | board thickness of the biological carrier pressing member 1 changes with scales and materials, it is about 0.5-10 mm in general.
[0015]
FIG. 2 shows a portion of the aerobic treatment tank 10 of the sewage purification tank using the biological carrier presser member 1 of the present invention, when the liquid in the tank is in WL (during operation). The aerobic treatment tank 10 is surrounded by the partition plate 4, the partition plate 5, and the outer tank 7, and a biological carrier support (water passage plate) 6b for holding the biological carrier is arranged in the lower part and in the upper part. The biological carrier pressing member 1 is arranged, and another biological carrier support (water passage plate) 6a is arranged at an intermediate position separating the upper half from the lower half. The planar plate-like portion 2 of the biological carrier surface pressing member 1 is usually submerged under the WL, while a part of the convex portion 3 is exposed on the WL.
[0016]
And the flow of sewage is the flow A as shown in FIG. 2 normally. In the vicinity of the biological carrier holding member 1 into which a highly concentrated liquid flows, biological cells (biofilm) tend to adhere to the hole (mesh) part of the holding member 1, and this becomes enlarged over time, closing the hole (mesh). Let By the way, even if the hole (mesh) of the flat plate-like portion 2 of the biological carrier pressing member 1 is closed and the liquid level rises slightly, the convex portion 3 is raised to a position higher than WL. Like the flow B as shown in FIG. 2, the inflow (advection) of the liquid from the hole (mesh) in the convex portion 3 to the lower part of the tank occurs to prevent an extreme rise in water level and liquid overflow to the next tank. it can.
[0017]
In addition, as time passes, biological cells (biofilm) adhere to the convex portion 3 and the holes (mesh) of the convex portion 3 also close. In this case, the biological carrier pressing member 1 that is completely submerged. The growth rate of biological cells (biofilms) is slower than when using. In addition, in general households, maintenance inspections are required once every four months or more. At that time, it is possible to keep the flow of sewage normal by cleaning the biological carrier pressing member 1. it can.
[0018]
FIG. 3 is a schematic configuration diagram of a sewage septic tank using the biological carrier pressing member 1. Next, the sewage septic tank of the present invention will be described with reference to this figure.
[0019]
The sewage septic tank has, from the upstream side, a sedimentation separation tank first chamber 14 that sediments sedimentary solids in the sewage under gravity (anaerobic), followed by a sedimentation separation second chamber 15, and is aerobic in the downstream flow. An aerobic treatment tank 10 for biological treatment (a biological reaction chamber 11 for biological treatment under aerobic conditions is formed in the upper part, and a filtration chamber 12 for filtering SS and transferring the filtrate to the next tank is formed in the lower part. ), A treated water tank 17 and a disinfection tank 18. Each of these tanks is partitioned by partition walls 9, 4, 5, 37, etc. However, SS means suspended suspended matter or sludge.
[0020]
In the precipitation separation tank first chamber 14 and the precipitation separation tank second chamber 15, in order to enhance the anaerobic biodegradation function, the tank can be filled with a filler (biological carrier, filter bed).
[0021]
In the biological reaction chamber 11, organic substances in the liquid are decomposed and removed by aerobic microorganisms. The tank is filled with a biological carrier suitable for holding and growing microorganisms to form an aerobic filter bed (for microbial reaction). The filter bed may be a fixed bed to which a biological carrier is fixed or a fluidized bed that flows together with the liquid. At this time, in order to maintain the aerobic condition, air is discharged from the blower 20 through the air diffusion member (air diffusion pipe) 39.
[0022]
The liquid flowing into the biological reaction chamber 11 flows downward through the aerobic filter bed in the chamber. Then, when organic matter is biodegraded, a part of it is converted into sludge, and sludge increases.
[0023]
In the filtration chamber 12, the SS flowing from the biological reaction chamber 11 is filtered, and the filtrate is transferred to the next tank. In order to filter and capture the sludge, a filtration filter bed filled with a filter medium is formed in the filtration chamber 12. The direction of the flow through the filter bed is a downward flow.
[0024]
Since the SS trapped in the filter bed for filtration is clogged, clogging or the like occurs, so regular backwashing is necessary. When a predetermined time comes, the timer 41 is activated and the blower 20 is operated. Air is sent to both the backwash pipe 21 and the air lift pump pipe (for backwash drainage return) 19 to perform backwashing. The backwash drainage liquid is returned to the precipitation separation tank first chamber 4 using an air lift pump pipe 19.
[0025]
In the disinfecting tank 18, Escherichia coli, bacteria, and the like are sterilized and disinfected with a disinfectant. The treated liquid after disinfection is discharged out of the sewage septic tank from the outlet 42.
[0026]
The sewage septic tank is provided with a manhole at the top so that maintenance and cleaning inside the tank can be easily performed, and a manhole cover 13 is attached to the manhole.
[0027]
In addition, the graph of FIG. 4 showed the result of the water level rise experiment using the sewage septic tank of FIG.
[0028]
【The invention's effect】
The biological carrier pressing member of the present invention has a simple structure and is unlikely to overflow due to blockage.
According to the sewage septic tank of the present invention, stable sewage treatment can be performed, and sampling at the time of maintenance and inspection, measurement of dissolved oxygen amount in liquid, hydrogen ion concentration, etc., confirmation of water quality, etc. can be easily performed. .
[Brief description of the drawings]
FIG. 1 is a perspective view (A) and a longitudinal sectional view (B) of a biological carrier pressing member of the present invention.
FIG. 2 is a longitudinal sectional view of an aerobic treatment tank using the biological carrier pressing member of the present invention.
3 is a sewage purification tank incorporating the aerobic treatment tank of FIG.
FIG. 4 is a graph showing the results of a water level rise experiment using the sewage septic tank of FIG.
FIG. 5 is a partial longitudinal sectional view of a sewage septic tank using a conventional biological carrier pressing member.
FIG. 6 is a partial vertical cross-sectional view of a sewage septic tank using another conventional biological carrier pressing member.
[Explanation of symbols]
1: Biological carrier holding member 2: Planar plate-like portion 3: Projection 4, 5: Partition plates 6a, 6b: Biological carrier support (water flow plate)
7: Outer tank 8: Biological carrier 9: Partition plate 10: Aerobic treatment tank (11 + 12)
11: (aerobic) biological reaction chamber 12: filtration chamber 13: manhole cover 14: precipitation separation tank first chamber 15: precipitation separation tank second chamber 17: treated water tank 18: disinfection tank 19: air lift pump 20: blower 21 : Backwash pipe 24: (Upper) water flow plate 25: (Middle) water flow plate 26: (Lower) water flow plate 39: Air diffusion pipe 41: Timer 42: Outlet WL: Liquid level

Claims (1)

An aerobic treatment tank and a biological carrier pressing member disposed in the aerobic processing tank, wherein the biological carrier pressing member includes a flat plate-like portion and a convex portion protruding upward from the flat plate-like portion; So that the flat plate-like part is below the liquid level in the tank of the aerobic treatment tank, and a part of the convex part is above the liquid level in the tank during the operation of the aerobic treatment tank. Sewage septic tank to be installed.

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