JP2949572B2 - Aeration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerator for purifying sewage by an activated sludge method (also referred to as an activated sludge method).

[0002]

2. Description of the Related Art Conventionally, as this type of aeration apparatus, there is known an aeration apparatus in which a stainless steel pipe having a large number of opening holes is extended and fixed in a zigzag shape or the like at the bottom of a concrete tank. . In this aeration apparatus, oxygen is efficiently distributed into the tank by air diffusion from the bottom of the tank, and the purification capability of wastewater is high. However, such an aeration apparatus has problems that the cost of the concrete tank itself is high and that a long construction period is required.

[0003] Instead of the aeration tank, there is known an assembled water tank in which the body of the tank is formed of a steel plate and the inside is covered with a waterproof sheet, or a tank in which a pond is dug and the inside is covered with a waterproof sheet. Have been.

A tank using this type of waterproof sheet is lower in cost and shorter in construction period than a concrete aeration tank. However, since the bottom of this aeration tank is covered with synthetic rubber or the like, the air diffuser cannot be fixed. On the other hand, the thickness of the waterproof sheet is about 1 to 2 mm. If the air diffuser is not fixed, the air diffuser may move or vibrate due to the repulsive force of the air ejected from the air diffuser or the circulating flow in the wastewater. By doing so, there is a fear that the waterproof sheet may be damaged. For this reason, in an aeration tank using such a waterproof sheet, the air diffuser is not submerged in the tank, but floats on the wastewater surface, pumps up the wastewater in the aeration tank by an internal impeller, and sprays the water toward the water surface. Was used.

[0005]

However, in the above-mentioned floating type sprinkler, the circulation of the wastewater caused by the injection water does not reach the deep part of the accumulated wastewater, the efficiency of oxygen transfer is insufficient, and the microorganisms in the deep part become inefficient. There is a problem that the growth of the sewage is suppressed, and the decomposition treatment speed of the sewage is reduced. This problem was particularly noticeable in the case of deep stabilization ponds.

[0006] In order to solve the above problems, an object of the present invention is to provide an aeration apparatus capable of further improving oxygen transfer efficiency and improving wastewater treatment efficiency without damaging a waterproof sheet. .

In order to solve the above problems, an aeration apparatus according to the present invention includes an aeration tank whose inside is covered with a waterproof sheet, and an air supply apparatus for supplying oxygen to wastewater. An air pump for supplying oxygen provided outside the tank, an air supply pipe extending from the air pump into the tank, an exhaust unit connected to the air supply pipe, and the aeration tank with the exhaust unit fixed. An aeration apparatus comprising: a weight plate that is settled at the bottom;
Outside the aeration layer to precipitate sludge in the treated water
Is settled down in the treated water in the settling tank
I decided to.

It is preferable that a base plate on which the weight plate is placed with the prevention sheet interposed therebetween is buried in the ground plane.

It is desirable that a floating type watering device for supplying oxygen from the surface of the wastewater is arranged so as to float above the sinking type air supply device.

[0010] In the present specification, "waste water" is water discharged from daily life, business and production activities, and means water that needs to be treated in principle. The oxygen supplied to the aeration tank is usually supplied by air.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an aeration apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view in which a part of the aeration device is cut away. The aeration apparatus 1 includes an aeration tank 3 whose inside is covered with a waterproof sheet 2 and stores wastewater, and a sinking type air supply apparatus 4 submerged in the wastewater. In the figure, reference numeral 5 denotes a raw water tank storing wastewater, and reference numeral 6 denotes a sedimentation tank for taking out treated water. In the wastewater (sewage) sent from the raw water tank 5 to the aeration tank 3 through the water pipe 8 by the pumping air pump 7, organic substances in the wastewater are decomposed by aeration. The water in the aeration tank 3 is sent from the surface layer to the settling tank 6 via the float pump 9, where the sludge is settled and taken out as treated water.

The aeration tank 3 has a built-in water tank known as an industrial water tank (for example, an industrial water tank T manufactured by Unitika).
-200) can be used. In this water tank, an annular concrete foundation 10 is disposed on the ground, a steel plate frame 11 is mounted on the foundation, and the inside is covered with a waterproof sheet 2. The illustrated frame 11 has, for example, a diameter of 10 mm.
~ 20 meters, the installation surface surrounded by the frame body 11,
It is preferable to dig in a mortar shape. In addition, the side wall of the aeration tank 3 may be formed by digging the ground instead of the frame, and the entire tank may be in the form of a pond.

In the sinking type air supply device 4, an exhaust portion 13 can be fixed to the upper surface of a cylindrical weight plate 12 via a fixing bracket or the like. The weight plate 12 can be formed of a block of concrete, metal, or the like having a specific gravity larger than that of water, and has a weight that does not float due to the buoyancy of oxygen. It is preferable to attach a sponge member (not shown) to the lower surface of the weight plate 12 so as not to damage the waterproof sheet 2. The diameter of the weight plate 12 is preferably about 1/5 of the diameter of the outer frame 11. The sinking type air supply device 4 is generally placed near the center of the circular aeration tank, and is disposed at the deepest part in the case of a mortar-shaped bottom surface. Depending on the size of the aeration tank 3, the sinking type air supply device 4 can be arranged at a plurality of locations.

The exhaust portion 13 can be formed by forming air diffusion holes 16 at equal intervals on the upper surface of a pipe formed in an annular shape. The exhaust part 13 is provided with a joint part 18 for connecting an air supply pipe 17 connected to an air pump P disposed outside the tank. The air pump P is
Submerged in the treated water in the sedimentation tank 6 located outside the aeration tank 3.
It is set down. The exhaust part 13 has an inner diameter of 12
It is desirable that the thickness is 0 mm to 150 mm and that it is formed of stainless steel. In addition, the annular form of the exhaust part 13 is as follows.
It is also possible to use single, double or more.

In order to stably mount the sinking type air supply device 4 on the bottom of the aeration tank 3, it is preferable to bury a base plate 19 in a sandy bottom G under the waterproof sheet 2. Stand plate 19
Can be formed in substantially the same planar shape as the weight plate 12, and similarly to the weight plate 12, can be formed of a block of concrete, metal, or the like. It is preferable that a fixing stake 20 is provided to protrude from the bottom surface of the base plate 19. In order to prevent the sinking of the base plate 19, it is preferable that, when the base plate 19 is installed, gravel stones are spread to form a foundation, and the foundation plate is placed on the foundation.

The waterproof sheet 2 is made of chloroprene rubber or the like.
A known synthetic rubber sheet (for example, Kanebo Kasei “Kanesheet” (registered trademark of Kanebo Co., Ltd.)) can be used, and its thickness can be 0.8 to 2.0 mm.

The sinking type air supply device 4 has a simple structure,
It is easy to manufacture and upsize, and can be provided at low cost.

If the bottom of the aeration tank 3 is formed in a mortar shape, ascending water flow generated by the elementary air injection from the sinking type air supply device 4 is applied to the surface layer and the frame 11 as shown by arrows in the figure. After flowing along the mortar-shaped inclined surface, it is easy to flow along the mortar-shaped inclined surface, so that sludge or the like is prevented from settling on the bottom of the aeration tank 3.

If the base plate 19 is buried,
The sinking type air supply device 4 can be stably mounted. In particular, the reaction force acting on the weight plate 12 of the sinking type air supply device 4 due to the injection of air from the air diffuser hole 16 is applied to the base plate 1.
Since the weight plate 9 is received, the weight plate 12 can be prevented from sinking to the sand bottom G via the waterproof sheet 2, and can be further stabilized.

It is preferable that the aeration device 1 further includes a floating type watering device 21. The floating type watering device 21 is provided with an impeller (not shown) inside, and a well-known device of a type that sucks wastewater from below and uniformly discharges it from the water surface in the circumferential direction (for example, Aerator ARS2. 2B
Shape) can be used. Preferably, this type of floating sprinkler 21 is located as close as possible directly above the sinking air supply. For this reason, the floating type air supply device is normally fixed in position by being locked to a wire W or a rope extending from the side wall of the aeration tank.

If the floating type watering device 21 is floated,
As shown in the figure, the wastewater at the bottom of the aeration tank 3 is forcibly raised by the air injected from the sinking type air supply device 4, and the upward flow is sent to the suction port 21a of the floating type air supply device 21,
Since the water is injected from the water surface in the circumferential direction, a forced circulation force is also applied to the flow of the surface of the wastewater, and the circulation efficiency in the wastewater can be improved. As described above, by improving the circulation capacity of the wastewater, the efficiency of oxygen transfer is improved, the activity of microorganisms is promoted, the decomposition rate of organic substances in the wastewater is improved, and thus the wastewater treatment capacity can be improved.

Further, by using the floating type water spray device 21 together, the synergistic effect of the injection of the floating type air diffuser 21 onto the wastewater surface and the jet air of the sinking type air diffuser 4 may cause some microorganisms in the wastewater. Since it has the function of dispersing organic or inorganic substances that are not oxidized into the air, the COD value can be reduced. With conventional aeration equipment, pollutants (CO
D) The removal rate is about 30%, but the floating sprinkler 21
According to the apparatus of the present invention used in combination, 60 to 90% can be removed.

Table 1 shows that the values of BOD and COD of water taken out as treated water from the aeration device A using the floating type watering device 21 and the conventional aeration device B using only a diffuser tube are measured every month. FIG. Raw water value is BO
D is 550-770 mg / l, COD is 420-540 mg / l
(Average / day).

[0025]

[Table 1]

The processing capacity of the aerator A is 100 tons / day,
The output of the pump P is 11 kw, the motor output for driving the aerator impeller is 2.2 kw, the aeration device B is a concrete rectangular tank, the processing capacity is 70 tons / day, and the pump output connected to the aeration pipe. 5.6 kW.

The measuring method of PH conforms to JIS.K.0102.12.1, the measuring method of BOD conforms to JIS.K0102.21 and 32.3, and the measuring method of COD conforms to JIS.K.0102.17. .

As is clear from Table 1, the aeration device using the floating type watering device 21 is not only BOD but also COD.
Have also been significantly removed.

As described above, according to the aeration apparatus according to the present invention, since the weight plate stably arranges the sinking type air supply apparatus at the tank bottom, the waterproof sheet is not damaged. Moreover, the upward flow can be forcibly generated from the bottom by the injection air injected from the exhaust portion of the air supply device. Since the sinking type air supply device is disposed substantially at the bottom of the aeration tank, the upward flow radially flows from near the center on the surface layer of the stagnant wastewater, further flows downward along the side wall, and then returns to the bottom again. A circulating force for returning to the center can be provided. Therefore, it is possible to provide an inexpensive aeration apparatus having a high wastewater treatment capacity capable of obtaining sufficient circulation.

[0030]

As is apparent from the above description, according to the aeration apparatus of the present invention, it is possible to improve the oxygen transfer efficiency and increase the wastewater treatment capacity without damaging the waterproof sheet.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of an aeration apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 aeration device 2 waterproof sheet 3 aeration tank 4 sinking type air supply device 5 raw water tank 6 treatment tank 11 frame 12 weight plate 13 exhaust unit 17 air supply pipe 19 base plate 21 floating type watering device P air pump

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C02F 3/14-3/26 C02F 7/00

Claims (3)

(57) [Claims] 1. An aeration tank whose inside is covered with a waterproof sheet, and an air supply device for supplying oxygen to waste water, wherein the air supply device is an air pump for supplying oxygen provided outside the tank. An air supply pipe extending from the air pump into the tank, an exhaust part connected to the air supply pipe, and a weight plate that is settled at the bottom of the aeration tank while the exhaust part is fixed. In the aeration apparatus, the air pump is used for aeration.
The aeration to settle the sludge in the treated water
Settled in the treated water in the treatment tank located outside the layer
An aeration device characterized by being performed . 2. The aeration apparatus according to claim 1, wherein a base plate on which the weight plate is placed with the prevention sheet interposed therebetween is buried in a ground plane. 3. The water sprinkling device for supplying oxygen from the surface of the wastewater is arranged so as to float above the submerged air supply device. The aeration device as described.