JPH0696156B2 - Oil water treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention physically and domestically discharges domestic wastewater and miscellaneous wastewater discharged from general houses, apartment houses, high-rise buildings, etc. The present invention relates to a device for biological adsorption decomposition treatment, particularly to a device for separating and treating oil water in the waste water.

[Conventional technology]

Conventionally, domestic wastewater, miscellaneous wastewater, and commercial wastewater have been physically or chemically mixed with or combined with fresh water, and if such wastewater is directly released to the natural world, it will be decomposed and purified only by natural purification. It is known that it is not possible to do so, and it has an adverse effect on the amount and concentration of the natural cycle or more.

Therefore, various wastewater treatment methods have been developed in order to prevent pollution by these wastewaters and to purify the environment. That is, there are solid-liquid separation method, filtration method and adsorption method as the physical treatment method, and domestic sludge method as the biological treatment method,
The domestic sludge system is effective in downsizing, simplicity, and economical efficiency of the equipment, especially in the small amount of surplus products, and the activated sludge system has become the main stream of wastewater treatment methods. By this method, except for special harmful substances, wastewater generated by normal living systems and business activities is easily biosorbed and decomposed by aerobic and anaerobic organisms and converted into inorganic substances such as CO ₂ and H ₂ O. And then returned to nature.

Here, as the activated sludge system, a pressure floating method as shown in FIG. 4 is known. That is, the wastewater is subjected to physical treatment such as screening, sedimentation, and flotation to separate and remove impurities, suspended matter, and released oil, and then flowed into the adjustment tank (21).
Homogenize water quality, adjust pH, etc. Then adjusting tank (21)
The wastewater stored in is sent to the pressure floating tank (22). Here, a polymer flocculant is added from the dissolution tank (23), and pressurized air is pumped to the pressurized flotation tank (22) by a pressure pump to levitate dirt with bubbles, and a certain amount of it is continuously aerated. Send to the tank (24). The wastewater that has entered the aeration tank (24) is aerated and mixed with the activated sludge for a certain period of time, and the organic matter is oxidatively decomposed. At this time, contaminants such as fine earth and sand are adsorbed by the sludge. Then, the mixed liquid of sludge and treated water in the aeration tank (24)
It is guided to the settling tank (25) by natural flow. Here, the mixed liquid is retained and the sludge is separated by sedimentation. After the oil and the coagulant are separated as a supernatant, the treated water is discharged. 95% or more of BOD in wastewater is removed by such an activated sludge treatment process.

[Problems to be Solved by the Invention]

However, since the apparatus is large in the above-mentioned pressure floating method, the installation area must be wide and the residence time is 2
It took a long time of up to 3 hours, and the running cost was high.

In addition, in the device using the above-mentioned pressure flotation method, wastewater is previously treated with a flocculant in the pressure flotation tank (22) to remove organic substances to some extent to reduce BOD, and then activated sludge is aerated in the aeration layer (24). Since the treatment is performed, the pressure floating tank (22) and the aeration tank (24) are required.

In particular, recently, the sewerage standards have become stricter, and the wastewater from the food service industry, etc., whose operating wastewater is 50 m ³ or more, is under the tendency that the oil content is regulated to 30 ppm or less in the normal hexane extractant value, and an urgent countermeasure is required.

In view of the above circumstances, the present invention is a domestic wastewater, sewage wastewater, particularly commercial wastewater is physically, biological adsorption decomposition treatment, above all, the separation treatment of the emulsified oil component in the wastewater as a single step of the two-step treatment step in a short time. It is an object of the present invention to make it possible to meet the above regulation value at a low price.

[Means for Solving the Problems]

The present invention, in order to solve the above problems, a reaction provided with an oil-water separation tank for separating raw water into floating oil and a sedimentable substance, a nonwoven fabric-like filter medium, a diffusion pipe for supplying oxygen to the filter medium, and a coagulant injection device. An oil and water treatment device consisting of a tank and a settling tank for separating sludge water flowing out from the reaction tank into fresh water and sludge, in particular, the filter medium is formed by laminating a plurality of non-woven fabric layers in the longitudinal direction, and the lower end of each non-woven fabric layer is bonded with an adhesive. It is configured as a focused oil-water separator.

[Operation] With the configuration of the present invention as described above, the raw water is first separated into the floating oil component and the sedimentable substance in the oil-water separation tank, the supernatant oil component is separated and extracted, and the solid substance is precipitated. Then, the waste water containing the emulsified oil separated liquid is fed into the reaction tank. A flocculant is added in the reaction tank, and the emulsified oil liquid is embraced by the flocculant and aggregated, and passes through the nonwoven fabric layer from the lower part of the filter medium composed of a plurality of nonwoven fabric layers laminated in the longitudinal direction together with air bubbles by the air diffuser. While the air bubbles are being pressed, they are pressed through a narrow filter bed and mixed and stirred, so that the sludge adhering to the surface of the filter medium is washed and floated. The floated oil agglomerates flow into the sedimentation tank together with the sludge, the sludge settles in the sedimentation tank, and the oil agglomerates float to the liquid surface of the sedimentation tank. The floated supernatant oil agglomerates are separated and the treated water is discharged. On the other hand, the sludge settling at the bottom of the settling tank is continuously returned to the oil-water separation tank and mixed again with the newly introduced wastewater.

〔Example〕

An embodiment of the oil and water treatment apparatus of the present invention will be described below with reference to the drawings.

The oil / water separation device comprises an oil / water separation tank (1), a reaction tank (2) and a sedimentation tank (3). In the oil-water separation tank (1), raw wastewater is introduced and separated into a floating component and a sedimentable substance due to the difference in specific gravity. A communication pipe (4) is provided between the oil / water separation tank (1) and the reaction tank (2), and wastewater is allowed to flow from the oil / water separation tank (1) to the reaction tank (2) between both tanks. Air is supplied to the bottom of the reaction tank (2), and an air diffuser (5) that disperses air bubbles in the liquid is provided. In addition, a large number of filter material layers (6) are provided upright in the reaction tank (2) so as to be orthogonal to the passage direction of the wastewater. The filter material layer (6) is made of, for example, a non-woven fabric in which synthetic fibers are entangled, and the lower end edge of the filter material layer (6) is cleaved from the middle in the thickness direction as shown in FIG. Insert the stainless wire (7) parallel to the edge direction. The cleaved edges of the filter layer (6) are then focused and the second
As shown in the figure (b), the wire is fixed at a fixed position by solidifying with a synthetic resin adhesive (8) so that both edges are tapered. As shown in FIG. 3, the both ends of the stainless wire (7) are connected to the window surface (9) of the opposing wall surface of the reaction tank (2).
Insert into the upper recess (10) and secure.

On the other hand, a coagulant injection device (11) is installed above the reaction tank (2), and an outflow pipe (12) is connected to the coagulant injection device (11) to connect the oil-water separation tank (1) and the reaction tank (2). The end of the outflow pipe (12) is faced above the communication pipe (4) with. A settling tank (3) is installed in parallel on the downstream side of the reaction tank (2), and a connecting pipe (13) is provided between the reaction tank (2) and the settling tank (3) to prevent overflow from the settling tank (3). It flows to 3). Pump (14) at the bottom of the settling basin (3)
Is installed and the communication pipe (15) is connected to the pump (14) to extend the communication pipe (15) above the oil / water separation tank (1) to remove a part of the sludge settling in the sedimentation tank (3). Return to the oil / water separation tank (1).

The operation of an example of the oil / water separation process will be described. Chubobara drainage flows into the oil-water separation tank (1) at 20 m ³ / day. In the oil / water separation tank (1), oil and fat having a small specific gravity floats on the liquid surface, and thus the floating oil and fat is separated and discharged periodically. On the other hand, sedimentable substances such as solids settle at the bottom of the oil / water separation tank (1).
On the other hand, the emulsified waste liquid in which oil and fat are emulsified and suspended flows into the reaction tank (2) through the communication pipe (4) while being mixed in the waste water.

In the reaction tank (2), the coagulant from the coagulant injection device (11) is added, and the emulsified liquid coagulates together with the bubbles diffused by the air diffuser pipe (5) between the taper surfaces of the lower end edges of the filter medium layer (6). Through the nonwoven layer. At this time, when passing through the gaps of the filter medium layer (6), the floating oil agglomerates are pressurized and mixed with stirring to peel off the activated sludge and filter membrane adhering to the nonwoven fabric layer to remove the filter medium layer (6). pass. And
These floating scums rise in a stable manner. The floating scum flows into the settling tank (3) through the communication pipe (13). On the other hand, a small amount of sludge settles at the bottom of the reaction tank, but floats along with bubbles, is decomposed and purified by the activated sludge in the filter material layer (6), and flows into the sedimentation tank (3) together with scum. Of the inflowing wastewater, sludge settles at the bottom of the settling basin (3), and oil aggregates float to the drainage surface of the settling basin (3). The floating oil agglomerates separate and discharge the supernatant, and the clarified treated water is discharged. The sludge settling at the bottom of the settling tank (3) is sucked by the pump (14) and returned to the oil / water separation tank (1) through the communication pipe (15).

〔The invention's effect〕

Since the present invention has the above-mentioned structure, it has the following effects.

(1) Since the oil agglomerate aggregated by the aggregating agent floats together with the air bubbles compressed through the narrow space of the filter bed of the non-woven fabric while mixing and stirring the waste water and the air, it exerts a pressure effect,
The filter bed can be washed.

(2) The levitated object (scum) can be levitated in a stable form in a short reaction time.

(3) Since biodegradation is performed by the filter bed, the amount of scum generated is small, and the treatment can be performed in a short time with simple aeration.

(4) Since the lower end of the filter medium is bundled with the adhesive, the oil agglomerates floating with the bubbles are not blocked in the filter medium and can pass through the filter medium in sequence.

The following shows the data obtained by treating the wastewater with the equipment of this example Raw wastewater BOD 1000ppm Raw wastewater COD 800ppm Raw wastewater Normal hexane value 200ppm Floating matter value (SS value) 500ppm Flocculant concentration 2% of raw wastewater PH 6.0- 8.0 Final BOD 300ppm or less Final COD 300ppm or less Final normal hexane value 30ppm or less Final SS value 100ppm or less Final PH 6.1 to 8.0 In this way, a treatment retention time of 50 minutes gives a BOD removal rate of 50% and normal hexane removal rate of 90%. Was given.

Although the device of the present invention has been described for separating oil and water discharged from the buncho, secondary treatment of raw wastewater that has been treated by general wastewater discharged from general buildings, precipitation method such as manure wastewater, activated sludge method, aeration method, etc. It is also effective for

[Brief description of drawings]

FIG. 1 is a schematic side view of an oil / water separator showing an embodiment of the present invention, and FIG. 2 (a) is a state in which a stainless steel wire of a filter material layer made of a non-woven fabric is cut off before the stainless wire is inserted from the edge. A side view, FIG. 2 (b) is a side view of a state in which the edge of the filter medium layer is solidified with a synthetic resin adhesive, FIG. 3 is a perspective view showing a part of the wall of the reaction tank, and FIG. FIG. 3 is a schematic view of a sewage treatment apparatus by the pressure floating method of FIG. (1) …… Oil water separation tank, (2) …… Reaction tank (3) …… Sedimentation tank, (5) …… Air diffuser (6) …… Filtration material layer, (7) …… Stainless wire (8) …… Synthetic resin adhesive (11) …… Coagulant injection device

Claims (2)

[Claims] 1. An oil-water separation tank for separating raw water into a floating oil and a sedimentation material, a reaction tank equipped with a nonwoven fabric-like filter medium, a diffusing pipe for supplying oxygen to the filter medium, and a coagulant injection device, and from the reaction chamber. An oil water treatment device comprising a settling tank for separating outflowed sludge water into fresh water and sludge. 2. A filter medium comprising a plurality of non-woven fabric layers laminated in the longitudinal direction,
The oil-water treatment device according to claim 1, wherein the lower ends of the respective nonwoven fabric layers are bundled with an adhesive.