JPH11156390A - Sewage treatment method and apparatus in sewage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage treatment method capable of strongly taking the open air in a sewage tank in large quantities without emptying the sewage tank such as a purifying tank or the like and an apparatus therefor. SOLUTION: Pipes 2a-2c are allowed to fall into a sewage tank from the outside of the sewage tank while suspended by a support chain 9 to be provided vertically. The lower part of the pipes 2a-2c is connected to the compressor 8 arranged on the ground through an air hose 7. By this constitution, compressed air is sent to the lower part of the pipes 2a-2c under pressure from the compressor 8 through the air hose 7 and sewage is sucked from the lower part of the pipes to be mixed with air within the pipes and forcibly emitted from the upper end of the pipes to be mixed with sewage to circulate sewage to purify the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating sewage in a sewage tank such as a septic tank. More specifically, the present invention relates to a sewage treatment method suitable for purifying sewage in which scum is formed on the surface. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, the following three methods are known as typical methods for treating sewage in which scum is formed on a surface such as a septic tank.

[0003] The first method is an aeration method in which air is pressure-fed into a tank from a blower (blower) installed outside the septic tank through an air pipe installed in the tank.

In this method, the static pressure of the blower is usually 50
At about 0 mmAq, the air discharged from the piping in the tank becomes bubbles like soap bubbles and only rises in the sewage,
Convection and stirring of sewage in the tank does not occur. In carrying out this method, it is necessary to perform work for emptying the septic tank and providing air piping, and it is necessary to take measures against the noise of the blower.

A second method is to install a submersible pump at the bottom of the septic tank. At the discharge port of the pump, an ejector and a ventilation pipe for sucking air from above the wastewater are attached, and the negative pressure of the ejector passes through the ventilation pipe. It sucks in outside air, mixes the discharge flow from the ejector with the outside air, discharges the mixture into the tank, and convects the wastewater in the tank.

However, the scum formed on the surface of the sewage is not stirred by such a discharge flow. In addition, the ejector portion is easily clogged, the life of the submersible pump is about six years, and regular maintenance is required. Also,
It is necessary to empty the septic tank when installing the submersible pump and vent pipe.

A third method is to install a submersible motor with a screw in a septic tank near the liquid surface. First, a base is installed at the bottom of the septic tank so that the submersible motor occupies a position about 50 cm below the liquid surface. Fix the underwater motor on the gantry. This underwater motor is provided with a ventilation pipe that sucks liquid-level air using the negative pressure of the screw. A suction plate is provided on the upper part of the motor so that scum on the water surface can be sucked in, and the sucked scum is mixed with air from a vent pipe, discharged and convected.

The life of the mechanical seal and the motor of this underwater motor is about six years, and the work for installing the gantry must be performed with the septic tank empty.

[0009]

However, in order to carry out any of the above-mentioned methods, it is necessary to empty the septic tank in advance and to carry out construction work, and the amount of air taken in by these methods is relatively small. Therefore, it is insufficient to purify scum and the like formed thick on the surface of sewage with aerobic microorganisms. In the method of installing a submersible pump or a submersible motor in a tank, a strong effect of a strong electric field formed around the submersible tank has a negative effect of reducing aerobic microorganisms of good bacteria.

The present invention has been made in view of the above-mentioned problems, and it is not necessary to empty a sewage tank such as a septic tank.
A large amount of outside air is taken into the sewage tank and the scum on the surface of the sewage can be purified by aerobic microorganisms by strong convection of the sewage, and an electric field that reduces good bacteria is generated. It is an object of the present invention to provide a method and an apparatus for treating sewage in a sewage tank without any wastewater.

[0011]

In order to achieve the above object, a method for treating sewage in a sewage tank according to the present invention uses a compressor installed on the ground in a hollow body standing upright so as to be buried in the sewage in the sewage tank. Of high-pressure air, and a high-pressure air mixed flow is discharged from the upper end of the hollow body into the sewage tank.

In the sewage treatment apparatus for a sewage tank according to the present invention, a hollow body erected from the outside of the sewage tank on its lower surface, a compressor installed on the ground, and the hollow body connected to the compressor. It consists of an air hose.

The above-mentioned hollow body can be installed on the bottom surface of the sewage tank by lowering the hollow body from above the outside of the sewage tank while suspending the hollow body in the sewage tank using a support means such as a chain, a wire or a rope. Since the amount of air supplied from the compressor is large and can be rapidly discharged into the hollow body, a mixed flow containing a large amount of air intermittently and powerfully flows from the upper end opening of the hollow body. Since the discharged water collides with the lower surface of the scum and strongly convects the wastewater, the aerobic microorganisms are extremely activated and the wastewater can be purified in a short period of time.

Preferably, a plurality of circumferentially separated legs are formed at the lower end of the hollow body, and the hollow body is suspended from the ground by a support means such as a chain, a wire, a rope, or the like, and the sewage tank is suspended. The inside of the sewage tank is formed so as to be communicable with the inside of the lower end of the hollow body through a space between the plurality of legs when the hollow body is erected. This facilitates the work of hanging the hollow body from above the outside of the sewage tank and installing the sewage through the hollow body.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

An apparatus 1 according to a first preferred embodiment of the present invention comprises a pipe 2 having a diameter of about 50 mm as shown in FIG.
Are connected in a straight line, and the weight is about 20 kg. In this embodiment, in order to connect the plurality of pipes 2a to 2c, the ends of upper and lower pipes having external threads externally threaded at upper and lower portions of the connection ring 3 having internal threads threaded on the inner peripheral surface, respectively. It is connected vertically by screwing. Note that these pipes 2a to 2c can be replaced with one long pipe. By setting the length of the pipe to at least 10 times the inner diameter, mixing of bubbles and liquid, which will be described later, is improved.

A skirt member 4 is provided at a lower end of the pipe 2a, and an upper end opening of the skirt member 4 is integrally welded to a lower end of the pipe 2a. Four leg pieces 5 are separated from each other and attached to the outer peripheral portion of the lower end of the skirt member 4 by welding or the like. The leg pieces 5 enable the pipe 2 to stand upright.

A skirt member 4 is formed at the lower peripheral portion of the pipe 2a.
A through-hole is formed above the air nozzle, and an air nozzle 6 is inserted and fixed through the through-hole. This air nozzle is formed of a hollow body having a U-shaped side surface, and one end thereof is a pipe 2a.
Forms an upward discharge part at the center of the pipe, and the other end forms an upward connecting part outside the pipe 2a. The inner diameter of the air nozzle 6 is, for example, about 6 mm, and the discharge portion thereof is formed to have a smaller inner diameter of about 3 mm.

One end of an air hose 7 is attached to a connection portion of the air nozzle 6, and the other end of the air hose 7 is connected to a discharge port of a compressor 8. The lower end of the support chain 9 is attached to the upper end of the pipe 2c.

The above-described apparatus of the present invention is installed in a septic tank as an example. To install the apparatus, a manhole of the septic tank is opened, and the pipe 2 and the air hose 7 connected thereto are inserted into the septic tank. I do. During this insertion, the pipe 2 is gradually lowered into the septic tank while the pipe is suspended almost vertically by the support chain 9. Then, as shown in FIG. 2, the leg piece 5 at the lower end of the pipe 2 is connected to the bottom wall A of the septic tank.
The upper end of the support chain 9 is fixed to the manhole B when the pipe 2 stands upright in the septic tank by contact with the pipe. The compressor 8 is on the ground, and the air hose 7 enters the septic tank through a through hole formed in the manhole B.

At this time, as shown in FIG. 2, the upper end opening of the pipe is located close to and below the scum C accumulated and formed in a floating state on the upper surface of the sewage, and the lower end of the pipe holds the sludge D. It penetrates and is stably installed on the bottom of the septic tank.

In this state, when the compressor 8 installed on the ground is driven, the compressed air passes through the air hose 7 from the discharge portion of the air nozzle 6 attached below the pipe 2 to the upper part of the pipe in a vigorous manner. The sludge D which is discharged as bubbles and accumulated at the bottom of the septic tank is sucked into the pipe 2 from the inside of the skirt member 4 through the space between the leg pieces 5-5 at the lower end of the pipe 2 and rises. While rising in the pipe 2, it mixes with myriad of air bubbles, moves toward the liquid surface, vigorously collides with the scum C just above the opening at the upper end of the pipe, and vigorously agitates it. Thereby, the aerobic microorganisms contained in the sewage are activated, and the scum can be decomposed in a relatively short period of time to purify the sewage.

The compressor 8 is preferably a pressure-opening / closing type oilless compressor. The output of the compressor used as an example is 0.75 Kw and the discharge pressure rises to 8.5 kg / cm ^2. Since 5 kg / cm ² is sufficient, it is preferable to incorporate a pressure reducing valve in order to keep the ejection time as long as possible. An on-off time can be freely set by connecting a solenoid valve and a timer to the compressor 8. However, when a compressor having an economical capacity is used, it is usually 1 unit.
Convection can be generated in the tank by continuous operation with an operation of turning on for 2 minutes and turning off for 2 minutes.

FIG. 3 shows a second embodiment of the present invention, in which the pipe support structure and the air nozzle structure at the lower end of the pipe 2 are improved.

That is, the outer periphery of the lower end of the skirt member 4 attached to the lower end of the pipe 2 in the same manner as in the first embodiment is fixed to a low rectangular table-like support base 10 having leg pieces 5 at four corners. . A through-hole 10a is formed in the center of the table-like support 10 so that the inside of the pipe 2 communicates with the lower part of the table-like support 10. An elbow 11 having an L-shaped side surface is fixedly supported by four narrow plate-like arms 12 on the axis of the pipe 2 below the table-like support base 10. An air nozzle 6a on a tube is screwed into an upper end opening of the elbow 11, and a lower end of an air hose 7 connected to the compressor 8 is mounted on a lower opening of the elbow 11.

In the second embodiment, similarly to the first embodiment, the compressed air fed from the compressor 8 is forced upward from the air hose 7 through the elbow 11 and the air nozzle 6a into the pipe. Since it is discharged as countless air bubbles, the sewage can be vigorously circulated and agitated, and the scum can be decomposed and purified in a relatively short period of time. However, in the second embodiment, since the air nozzle 6a is screwed to the elbow 11, the air nozzle 6a is replaced with a new air nozzle having a different diameter depending on the size of the purification tank or the capacity of the compressor. There is an advantage that the work of replacing with 6a can be easily performed.

As a modification of the second embodiment,
If a cap (not shown) having a through-hole having a predetermined diameter is screwed onto the upper end of the air nozzle 6a,
The replacement operation can be further simplified by exchanging another cap having a through hole having a diameter different from that of the through hole.

The present invention is not limited to the preferred embodiment described above, and various modifications are possible within the scope of the appended claims. For example, a hollow body other than a pipe may be adopted, Wires, ropes, etc. can be used in addition to the support chains.

-Examples- Table 1 below shows the results obtained when sewage from a 30-ton combined tank was treated using the apparatus of the present invention.

[Table 1]

As is clear from Table 1, 60 days after using the apparatus of the present invention, the sewage changes from weakly acidic to slightly alkaline, and BOD (Biochemical Oxygen Demand), CO2
D (chemical oxygen demand) and SS (suspended matter) are significantly improved.

The amounts of hydrogen sulfide and methyl mercaptan, which are the causes of the offensive odor, were greatly reduced by the aeration, stirring and convection of the present invention, and the offensive odor disappeared. The reason is that the sulfate (SO ₄ ²⁻ ) in the water is decomposed into sulfate reducing bacteria, and S ²⁻ + 2H ₂ O
+ CO ₂ . The generated sulfide S ^2- is a hydrogen ion 2
Reacts with H ⁺ to generate hydrogen sulfide. Sulfate-reducing bacteria are typical anaerobic bacteria that produce hydrogen sulfate as a result of reacting hydrogen with sulfur or sulfuric acid instead of oxygen.
The increase of dissolved oxygen by sufficient aeration was able to eradicate anaerobic bacteria.

Although the BOD, COD, and SS values described above have been considerably improved by the apparatus of the present invention, further improvements are difficult with the present apparatus alone. The cause is mainly due to the normal hexane extract. The oil particles disperse, stabilize, and repel the droplets of the surfactant of the detergent, and form an emulsion that is dissolved and emulsified in water. In order to decompose the activated sludge, a method of introducing a dedicated aerobic microorganism is most suitable in view of the activated sludge method.
Then, an aerobic microorganism (300 g of perlite granules) having a high oil-decomposing ability was put into the tank after the treatment for 60 days in the present invention, and the measurement was made 40 days later. As a result, the result was greatly improved.

[0033]

As described above, in the method and apparatus for treating sewage in a sewage tank according to the present invention, the hollow body is suspended from above the outside of the sewage tank using a support means such as a chain, wire, or rope. Since it can be lowered and installed on the bottom in the sewage tank, there is no need to empty a sewage tank such as a septic tank, and the installation is extremely simple. Since the amount of air supplied from the compressor is large and can be rapidly discharged into the hollow body, a mixed flow containing a large amount of air is discharged intermittently and strongly from the upper end opening of the hollow body. Then, it collides with the lower surface of the scum and crushes and agitates the scum to strongly convect the wastewater, so that the aerobic microorganisms are extremely activated and the wastewater can be purified in a short time.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view showing a state where the apparatus of the present invention is installed in a septic tank.

FIG. 3 is a perspective view showing an apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 This invention apparatus 2, 2a-2C Pipe 3 Connecting ring 4 Skirt member 5 Leg piece 6, 6a Air nozzle 7 Air hose 8 Compressor 9 Support chain

Claims (4)

[Claims] 1. A high-pressure air is pumped from a compressor installed on the ground to a hollow body erected so as to be buried in sewage in a sewage tank, and a high-pressure air mixed flow is discharged from the upper end of the hollow body into the sewage tank. A method for treating sewage in a sewage tank, comprising: 2. The hollow body is erected in a sewage tank in which the surface of the sewage is covered with scum, and the upper end of the hollow body is positioned close to below the scum, and 2. The high-pressure air is pumped to the housing.
A sewage treatment method in the sewage tank described in the above. 3. A sewage tank comprising a hollow body erected from the outside of the sewage tank on its lower surface, a compressor installed on the ground, and an air hose connecting the hollow body to the compressor. Wastewater treatment equipment. 4. The hollow body has a plurality of legs circumferentially separated at a lower end thereof, and the hollow body is suspended from the ground by a support means such as a chain, a wire, a rope, or the like, and the inner bottom surface of the sewage tank is suspended. The sewage tank is formed so as to be able to communicate with the inside of the lower end of the hollow body through a gap between the plurality of legs when the hollow body is erected. A sewage treatment apparatus in the sewage tank according to 3.