JP2572336B2 - Organic wastewater filtration method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filtering and removing SS from organic wastewater such as sewage and washing a filtration layer.
TECHNICAL FIELD The present invention relates to a novel filtering device and a cleaning method for preventing a bad odor from being emitted.

[0002]

2. Description of the Related Art Conventionally, a process of precipitating SS in sewage and then biologically treating the same has been typical. However, the precipitation method has a drawback that the SS removal rate is low and the SS separation speed is low. Recently, instead of the precipitation method, a method has been attempted in which sewage is supplied to a filtration layer filled with large granular filter media (such as hollow plastic granules) to filter and remove SS. (Japanese Unexamined Patent Publication (Kokai) No. 2-17908) In this filtration device, the water surface is open to the atmosphere. To clean the filtration layer, air is sent to the lower part of the filtration layer by a blower, and the particulate filter medium is stirred by the rising motion of air bubbles. Meanwhile, a method of draining all the water in the filtration layer is employed.

[0003] The inventor of the present invention has repeated the technique described in JP-A-2-17908 for the purpose of treating sewage, and found that a large amount of organic SS was trapped in the filtration layer filled with the particulate filter medium. It has been found that when the filtration layer is washed with air, bad odors such as H ₂ S, mercaptan and ammonia volatilize to the outside. This phenomenon was particularly acute in summer when the water temperature was high.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively solve the problem of the generation of offensive odor during the conventional cleaning of a filter. As one method, of course, it is conceivable to deodorize by guiding a bad odor discharged at the time of air washing (hereinafter simply abbreviated as an empty washing) of the filtration layer to a separately provided deodorizing device, but a deodorizing device, a blower, There is a drawback that expensive equipment such as pipes is required. An object of the present invention is to prevent a malodor generation trouble extremely effectively without using such a method.

[0005]

The above objects can be effectively solved by the following means of the present invention. That is, (1) In a method of filtering organic sewage in which sewage is passed through a granular filter medium packed layer provided in a tank, when washing the granular filter medium packed layer, gas is removed from a space that can be hermetically sealed above the packed layer. A method for filtering organic sewage, comprising sucking and introducing water into the lower portion of the packed bed, and draining water in the packed bed from the bottom of the tank to wash the packed bed. (2) A granular filter medium packed bed is provided below the water surface in the tank, a sealed space is provided above the water surface where external air can be introduced, and gas is sucked from the space to discharge gas from the space below the packed bed. An organic sewage filtration device comprising a flow path and a gas discharge pipe, a blower provided in the flow path, and a drainage section provided at the bottom of the tank. It is.

(Configuration) An example of the configuration of the present invention will be described below with reference to FIG. However, the present invention is not limited to the following examples. In FIG. 1, reference numeral 1 denotes a filtration tank, and the tank 1 has a packed bed A filled with a granular filter medium. The granular filter medium preferably has a specific gravity enough to be easily disturbed at the time of empty washing, and its material, shape, and particle size are appropriately selected depending on the properties of the wastewater to be treated. For example, a preferable material for sewage or the like has a particle size of 10 to 30.
mm hollow plastic filter media can be used.

[0007] An organic wastewater inflow section 2 is provided below the packed bed A in the tank 1, and a filtered water outflow section 3 is provided above the bed A. The location of the filtered water outflow section 3 The water surface 4 of the tank 1 is determined by this. Above the water surface 4 of the tank 1, a sealable space B having a cover 6 is provided. The space B is connected to a blower (blower) 8 via a gas suction line 7, and further has a gas suction line. It is connected to a gas discharge pipe 9 through which gas is blown into the tank 1. An upper porous member (grating) 10 and a lower porous member 11 for preventing the granular filter medium from flowing out are provided on the upper and lower portions of the packed layer A, respectively. A drain section 5 having a valve 12 is provided at the bottom of the tank, and a gas inlet pipe 14 having a valve 13 is provided at the top of the tank (cover 6) so that outside air can flow into the space B. This gas inflow pipe 14 is a pipe that plays an important role in the filtration method of the present invention. The height of the space B may be such that water does not enter the gas suction line 7 when the blower 8 is started, and the height is not particularly limited.

[0008] The filter tank of the present invention having the above-described structure normally performs a filtration process of sewage in an upward flow without performing aeration during the operation for the filtration process. Thus, as the wastewater is filtered by operating the filtration device of the present invention, SS in the organic wastewater is filtered by the packed bed A, and filtered water having an SS of 30 mg / liter or less is obtained. If the time filtration is continued, a large amount of SS leaks into the filtered water. At this point, the supply of organic sewage is stopped, and by the unique method of the present invention described in the following operation, emission of odor is prevented. In addition, the filling layer A is washed.

(Operation) A method for cleaning the packed bed A of the filtration tank 1 of the present invention will be described with reference to FIG. 1) Drive the blower 8 to suck the gas in the space B,
The gas is ejected from the gas discharge pipe 9 into the tank 1, and the granular filter medium in the packed bed A is violently disturbed by the upward movement of the bubbles. This operation is continued for a few minutes. At this time, the odor is released from the packed bed A, but the gas discharged from the gas discharge pipe 9 by the blower 8 rises in the packed bed A, reaches the space B, and passes through the gas suction pipe 7 again. Since it is sucked and circulated by the blower 8, no bad odor is leaked to the outside. This is one of the points of the present invention, and there is no conventional example of washing the filtration layer while circulating the gas.

2) When the valve 12 is opened and the water in the filtration tank is drained to the lower grating 11 while the blower 8 is driven, SS trapped in the packed bed A is discharged out of the tank. The outside air introduction passage 14 plays an important role in this operation. If the outside air introduction path 14 does not exist, even if the valve 13 is opened, the inside of the tank has a negative pressure and cannot be drained at all, so that the packed bed A cannot be washed. When the valve 13 is opened while the blower 8 is driven, the water in the filtration tank is drained.
Since the gas flows into the tank 1 from the tank 4, the inside of the tank 1 does not have a negative pressure, so that the water can be smoothly drained from the pipe of the drainage unit 5. Preferably, the drain is performed rapidly. After draining is completed, the blower 8 is stopped, the valve 12 is closed, and the operation 2) is completed.

As described above, the filling layer A can be washed without releasing a bad odor to the outside. Note that the filtered water outflow section 3 may also serve as the outside air introduction path without providing the outside air introduction path 14 in the closed cover 6. That is, when the valve 12 is opened and drained, outside air may flow through the filtered water outflow passage 3. And again, organic sewage 2
When the filtration process is restarted, the water level in the tank 1 rises little by little, and the gas in the tank 1 is gradually discharged to the outside through the outside air introduction passage 14 as the water level rises. Therefore, it can be easily disposed of in any way. For example, in the post-step of the filtration step of the present invention, a biological treatment facility for activated sludge treatment or the like is usually provided, and the above-mentioned small amount of odorous gas is led to a blower chamber for aeration of this activated sludge treatment, along with a large amount of air, It is reasonable to send it to the aeration tank for biological deodorization.

[0012]

【The invention's effect】

(1) The organic SS in the organic sewage can be effectively removed by filtration, and the odor does not diffuse outside even when the filtration layer is washed. Therefore, no special deodorizing equipment is required, which is extremely reasonable. (2) Since the odor does not diffuse to the outside, the filtration layer can be washed with a sufficient amount of gas. (Conventionally, since the filtration layer is washed with air, the same amount of odorous gas as the amount of washing air used is discharged outside the system.)

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of a device showing the operation of the filtration device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration tank 2 Organic wastewater inflow part 3 Filtration water outflow part 4 Water level in tank 5 Drainage part 6 Cover 7 Gas suction line 8 Blower 9 Gas discharge pipe 10 Upper porous member 11 Lower porous member 12 Valve 13 Valve 14 Gas Inflow pipe A Packed bed B Space

Claims (2)

(57) [Claims] 1. A method for filtering organic sewage, wherein sewage is passed through a granular filter medium packed layer provided in a tank, wherein gas is removed from a hermetically sealed space above the packed layer when the granular filter medium packed layer is washed. A method for filtering organic sewage, comprising sucking and introducing water into the lower portion of the packed bed, and draining water in the packed bed from the bottom of the tank to wash the packed bed. 2. A granular filter medium-filled layer is provided below the water surface in the tank, a sealed space is provided above the water surface where external air can be introduced, and gas is sucked from the space to remove gas from the space below the packed layer. An organic sewage filtration device, comprising: a discharge channel and a gas discharge pipe; a blower provided in the flow channel; and a drainage section provided at the bottom of the tank.