JP3062561B2 - Oil-water separator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-water separation apparatus that floats and separates oil by passing treated water such as sewage mixed with oil through a plurality of water tanks arranged in series. It is.

[Prior art] At workplaces where oil may flow to the floor on a daily basis, such as a car repair or dismantling factory, a machine shop, or a gasoline filling station, drainage such as floor washing water and rainwater is collected in a gutter. After being discharged, it is sent to an oil-water separator, where the oil is removed and then discharged into sewage or rivers.

Conventional oil-water separators include so-called API oil separators that conform to the design standards of the American Petroleum Institute, PPI oil separators in which multiple rows of inclined plates are arranged in tanks, and CPI oil separators that use wavy inclined plates. Yes, in principle, it is mainly an ordinary horizontal flow sedimentation tank or a gravity separation type combining an inclined plate with it.

[Problems to be Solved by the Invention] In the conventional API oil separator, in order to keep the average flow velocity of the water to be treated in the tank below the limit value, the length of the tank decreases as the size of the oil droplet to be removed decreases. The disadvantage is that a long equipment area is required to remove suspended oil droplets in the water to be treated almost completely, and an additional filter-type oil removal device must be provided. Was.

In addition, PPI oil separators and CPI oil separators have complicated tank structures and large scales, require special techniques for handling and maintenance, and have a limit in the ability of the treatment capacity to follow fluctuations in the flow rate of water to be treated. For the treatment of wastewater containing oil such as in an outdoor factory, it is inevitable that the oil will be mixed into the wastewater in rainy weather.

The present invention is suitable for oil-water separation of oil-containing wastewater particularly in a facility where rainwater may be mixed, and provides an oil-water separation device that can be configured with a relatively small facility area by a prefabricated assembly system or unitization. Is what you do.

[MEANS FOR SOLVING THE PROBLEMS] The oil-water separation device according to the first aspect of the present invention floats and separates oil by passing treated water such as sewage mixed with oil through a plurality of water tanks arranged in series. In particular, in order to achieve the above-described object, a receiving tank for receiving the water to be treated from an upper opening, and a series of upstream to downstream for sequentially receiving and calming the water to be treated in the receiving tank. A plurality of stages of sedation tanks arranged in a shape, an oil collection tank that takes in, as an overflow, mainly floating oil on the surface layer of the water to be treated in at least the sedation tank at the downstream end, and oil water taken into the oil collection tank. A circulation pump means for returning the water to the receiving tank; and a discharge means for discharging the oil-separated water to the outside from the bottom of the calming tank at the downstream end.

In the oil-water separation device according to the second aspect of the invention,
4. The oil-water separation device according to claim 3, wherein the sedation tank includes a pair of adjacent sedation tanks that communicate with each other at a bottom portion, and further includes a surface layer in a sedation tank on a downstream side of the adjacent sedation tanks. And further includes another sedation tank communicated with.

In the oil-water separation device according to the invention of claim 4,
The receiving tank is connected to the sedation tank at the upstream end by a rising channel just above the sludge reservoir at the bottom thereof.

In the oil-water separation device according to the invention of claim 5,
Since the receiving tank receives the return of the oil water by the circulation pump means and the final collection and removal of the oil is performed by a vacuum car or the like from the receiving tank, the receiving tank has a larger capacity than the individual tanks of the calming tank. It was done.

In the oil-water separation device according to the invention of claim 6,
Control means for detecting the level of the surface oil water of the surface oil of the downstream sedation tank overflowing into the oil collecting tank and controlling the drive of the circulating pump means so as to maintain the overflow is further provided. It is provided.

In the oil-water separation device according to the invention of claim 7,
The oil collecting tank is provided with an independent container positioned so that an upper edge thereof slightly sinks below the surface of the water to be treated in the calming tank at the downstream end.

An oil-water separation device according to an eighth aspect of the present invention is configured such that the independent container is suspended and supported in the water to be treated by a floater principle. In the oil-water separation device according to the ninth aspect, the independent container is supported by a support. The height position of the upper edge is supported so as to be adjustable.

Further, in the oil-water separation device according to the tenth aspect, in the oil-water separation device according to the seventh aspect, the circulating pump means includes a submersible pump disposed in the independent vessel.

[Operation] In the oil-water separation device according to the first aspect of the present invention, when water to be treated such as sewage mixed with oil is passed through water tanks arranged in series in a plurality of stages to separate the oil by flotation, The water to be treated flows into the receiving tank from its upper opening. In the receiving tank, turbulence is generated near the surface layer and mixing occurs, but in the relatively deep bottom layer, mixing due to turbulent flow is slight, and therefore, separation by floating of oil occurs in the receiving tank. I have. The water to be treated in the lower part of the receiving tank is guided to the upstream end of the multistage calming tank, and the turbulence of the flow is calmed down toward the downstream to promote the generation of floating oil. There is an oil collecting tank at least at the downstream end of these calming tanks, and when the surface layer of the water to be treated flows into the oil collecting tank as overflow, the oil floating on the surface layer is rapidly taken into the oil collecting tank at a high flow rate. It is. The oil water taken into the oil collecting tank contains oil at a high ratio, and the overflow having a high oil concentration is returned to the receiving tank from the upper opening thereof by the circulation pump means. On the other hand, water containing almost no oil remains at the bottom of the downstream end of the calming tank, and thus the oil-separated water flows out from the downstream side of the calming tank to an external discharge system and is discharged. You.

In the oil / water separation device of the present invention, since the oil water having a high oil content is recirculated by the oil collection tank and the circulation pump means from the downstream calming tank to the upstream receiving tank, the circulation of the oil water by the reflux is continued. Then, the floating oil gradually accumulates in the upper tank of the receiving tank. The floating oil in the upper layer of this receiving tank is
When the receiving tank is observed from the upper opening, it can be easily visually confirmed, but of course, the state of the pool may be automatically detected by an oil detector installed at an appropriate depth. When the floating oil has accumulated to a certain degree in the upper layer of the receiving tank, the floating oil may be suctioned by a vacuum and treated by an oil processing company. At this time, it is convenient if the settled sludge collected at the bottom of the receiving tank is suctioned by vacuum.

In this way, the floating oil and sludge are sucked and removed from the receiving tank regularly or irregularly, so that the separated oil and the sludge can be efficiently collected. Since efficient oil removal is performed, almost no oil is recognized in the treated wastewater that is taken out from the bottom of the calming tank at the downstream end and discharged to the outside.

The configuration of each tank of the oil-water separation device of the present invention is extremely simple as compared with the conventional one. Therefore, the tank configuration can be prefabricated by welding and assembly using a normal iron plate or the like, or provided as a molded article made of fiber reinforced plastic. Can also. This eliminates the need for the curing period required for the conventional concrete cast-in-place structure, so that the oil-water separator can be installed overnight, for example, without hindering other business uses at the installation site such as a gasoline filling station. Can be realized. In the present invention, it is practically desirable to constitute the prefabricated structure or the molded body as described above, but, of course, the present invention can also be applied to concrete structures.
Further, in the present invention, it is not obstructive to promote the floating of the oil particles by vertically arranging the baffle plate parallel to the flow slightly in the appropriate sedation tank.

In the oil-water separation device according to the second aspect of the invention,
The calming tank includes a pair of adjacent calming tanks that communicate with each other at the bottom, whereby the water to be treated separated from the floating oil in the calming tank on the upstream side of the pair flows into the calming tank on the downstream side from the bottom and remains. The efficiency of the gravitational separation of the oil particles is maximized so that the oil particles can be efficiently floated, and thus the efficient floating separation of the oil can be achieved in each of the adjacent sedation tanks. in this case,
Preferably, the bottom communication port between adjacent calming tanks has a wide opening in order to make the flow as laminar as possible as little as possible.

In the oil-water separation device according to claim 3, another sedation tank connected to the downstream sedation tank among the adjacent sedation tanks at the surface portion is further provided, and the collection is performed in the other sedation tank. An oil tank can be installed. In this way, the floating oil floating on the surface layer of the upstream sedation tank is shifted to the other sedation tank as a laminar flow,
The floating oil can be taken into the oil collecting tank without disturbing the floating separation of the oil in the immediately upstream upstream calming tank. Also in this case, it is needless to say that the communication at the surface layer is preferably achieved by a wide or full width passage.

In the oil-water separation device according to the invention of claim 4,
The receiving tank is communicated with the upstream end of the calming tank by a rising channel just above the sludge reservoir at the bottom thereof. By introducing the sludge at the upstream end, it is possible to prevent the sludge at the bottom of the receiving tank from flowing into the calming tank at the same time as avoiding excessive mixing of oil particles.

In the oil-water separation device according to the invention of claim 5,
Since the receiving tank receives the return of the oil water by the circulation pump means and the final collection and removal of the oil is performed by suction from the receiving tank by vacuum or the like, the receiving tank has a larger capacity than the individual tanks of the calming tank. Thus, the storage capacity of the floating oil is increased, and the interval of the suction operation is given a margin.

In the oil-water separation device according to the invention of claim 6,
Control means for detecting the level of the surface oil water of the surface oil of the downstream sedation tank overflowing into the oil collecting tank and controlling the drive of the circulating pump means so as to maintain the overflow is further provided. With this, even if the water depth at the upper edge of the oil collecting tank is constant, the circulation processing of the oil water is performed stably according to the flow rate of the inflow sewage, and it becomes possible to prevent the oil component from being mixed in the discharged water. .

In the present invention, a plurality of circulating systems of the floating oil by the oil collecting tank and the circulating pump means may be provided in a multiplex manner. In this case, preferably, the oil collecting tanks are arranged in a plurality of calming tanks on the downstream side. It is preferable that all the reflux from each oil collecting tank is circulated to the receiving tank. Further, in this case, the control means may include a function of selectively operating some of the circulating systems according to the flow rate of inflow of sewage from outside.

In the oil-water separation device according to the invention of claim 7,
The oil collecting tank is provided with an independent container positioned so that an upper edge thereof slightly sinks below the surface of the water to be treated in the calming tank at the downstream end. This is because the oil collecting tank is placed in the water surface area of the calming tank, the overflow is taken in from the entire periphery of the oil collecting tank, and the flow of the surface tank in the calming tank at the downstream end is made to flow from the entire periphery to the center, so that the floating oil is removed. As well as being able to collect quickly,
This is to prevent a deviated flow toward any one of the edges from being generated on the surface layer of the sedation tank at the downstream end, thereby eliminating poor separation due to uneven distribution of floating oil on the surface layer.

In the oil-water separation device according to the invention of claim 8, the immersion depth of the independent oil collecting tank is naturally achieved by buoyancy balance by floatingly supporting the independent container in the water to be treated by the principle of a float. Was done,
In this case, another floating member may be attached to the independent container, or the container itself may be configured to function as a floating member.

In the oil-water separation device according to the ninth aspect, the height position of the upper edge can be adjusted by supporting the independent container by a column, whereby the deposition depth of the independent oil collecting tank can be adjusted according to the water level of the water to be treated. It is like that.

Further, in the oil-water separation device according to the invention according to claim 10, in the oil-water separation device according to claim 7, the pump of the circulation pump means is a submersible pump arranged in the independent container, and maintenance and inspection of the pump are performed. It was made easier. In this case, if the independent oil collecting container with the pump is configured to be detachable from the sedation tank, the collected oil can be collected from the receiving tank to another container by using this.

Various features of the present invention will be more clearly understood from the following description of the embodiments with reference to the drawings.

[Embodiment] FIG. 1 is a schematic vertical sectional view showing an oil-water separator according to a preferred embodiment of the present invention. FIG. 2 is a plan view thereof.

1 and 2, this apparatus constitutes a unit 1 in which a main tank structure is integrated by welding a metal plate, molding a fiber-reinforced plastic, or the like. Unit 1
Has a multi-stage tank structure in which a plurality of rigid tanks are arranged side by side in a row as a whole, and connection portions 1a and 1b with the side grooves are formed at the upstream end and the downstream end, respectively. .

The entrance-side connection part 1a opens to the receiving tank 10, and downstream of the receiving tank 10, the first to third sedation tanks 11 to 13 and the inspection tank 14 are arranged in order. The lowermost inspection tank communicates with the discharge side groove 1b at the downstream end.

From the receiving tank 10, the water to be treated in a relatively lower part thereof is discharged to the surface of the first calming tank 11 through a rising pipe 15, and the lower end of the rising pipe 15 has a simple sludge repellent. A filter is installed.

The first sedation tank 11 is in direct communication with the second sedation tank 12 at a relatively lower portion thereof by a wide hole 16 formed in a partition wall of the first sedation tank 12.

The second calming tank 12 is directly communicated with the third calming tank 13 at the surface layer by a wide recess 17 formed on the upper edge of the partition wall with the third calming tank 13.

With such a communication structure, the water to be treated, which has flowed into the receiving tank 10 from the inlet-side connecting portion 1a, flows along a path meandering up and down to the second calming tank 12.

The flow from the second calming tank 12 to the third calming tank 13 is a simple horizontal shift flow of only the surface layer.

A floating floating oil collecting tank 20 is arranged in the third calming tank 13, and the oil collecting tank 20 has a submersible pump inside.
It has 21. The pump 21 is controlled by the control panel 30 so as to operate only while the level of the water to be treated in the oil collecting tank 20 is detected to be equal to or higher than a predetermined level by a level switch (not shown) fixed to the oil collecting tank 20. The treated water pumped up by the pump 21 is
Preferably, it is returned to the receiving tank 10 by a pipe 22 including a flexible portion. In this case, even when the switch does not generate the detection output, the water to be treated is contained in the oil collecting tank 20 at a level higher than the pump suction port so that the internal pump 21 does not suck air. In this state, the floating balance of the oil collecting tank 20 is balanced so that the upper end of the oil collecting tank 20 is sunk at a predetermined depth from the water surface level of the third calming tank 13. Therefore, the water to be treated on the surface layer continuously flows into the oil collecting tank 20, but the pump 21 is driven so that the level of the inflowing water to be treated in the oil collecting tank does not catch up with the third calming tank water level.

The third sedation tank 13 and the inspection tank 14 downstream thereof are connected by a riser pipe 18 having one end opened to the lower part of the third sedation tank 13, and the upper end of the riser pipe 18 is connected to the inspection tank 14. Open near the water surface level.

The inspection tank 14 has an oil shield 19 in the middle of the flow, and the flow passes through the lower end of the oil shield 19 and flows out from the outlet connection portion 1b to the drain groove. Note that the oil barrier 19 may be a part of the wall structure of the unit 1.

In the oil-water separator of this embodiment, the water to be treated for mixing the oil-water from the gutter flowing into the receiving tank 10 from the inlet-side connecting portion 1a flows into the surface oil layer of the receiving tank 10 and descends while entraining the oil. However, the receiving tank 10 may be provided with a partition plate or a wall 23 as shown by a dashed line in FIG. 1 in order to use the receiving tank 10 for collecting oil from a surface layer by vacuum in another tank or the like. Now, the water to be treated that has flowed into the receiving tank 10 flows down while entraining the oil in the layer and floats up the oil particles with a slight sedation effect while mixing some oil particles in the width direction to form two rising pipes. It flows into the first sedation tank 11 via 15 from its surface.
In the first calming tank 11, the flow is near the surface from the two risers 15, so that the disturbance is small, so that the treated water effectively floats the calmed oil particles. The water to be treated, which is low in oil particles in the lower layer, then flows into the second calming tank 12 from below through the wide hole 16, where the hole 16 is wide and is not disturbed.

The water to be treated that flows into the second calming tank 12 from below is caused to float by exerting a sufficient buoyancy effect on the oil particles, and the oil remaining on the surface layer is almost floated. This second calming tank
The water to be treated in the surface layer 12 of FIG. 12 shifts horizontally together with the floating oil through the wide concave portion 17 and flows into the third calming tank 13 where the oil collecting tank 20 has the surface layer as described above. Therefore, most of the surface floating oil flows into the oil collecting tank 20. The water that escaped into the oil collecting tank 20 was water containing almost no oil particles, which flowed from the lower layer of the third calming tank 13 through the riser pipe 18 to the surface level of the inspection tank 14, It passes under the shield plate 19 and flows out from the outlet connection portion 1b to the drainage ditch. The upstream side of the plate 18 of the inspection tank 14 is used for visual inspection of the surface of the final drainage, and if oil on the surface is recognized, surface water is recirculated.

On the other hand, the water to be treated collected in the oil collecting tank 20 is the third calming tank.
It is an oil-water mixture containing a large amount of oil because most of the surface oil on the surface of 13 is recovered. This mixture is pumped by pump 21
It is circulated to the receiving tank 10 via 22. In this case, the outlet of the pipe 22 may be located on the upstream side of the partition plate 23 shown by a chain line in FIG. 1, so that the surface portion of the receiving tank 10 on the downstream side of the partition plate 23 is provided with an oil recovery work area by vacuum or the like. Can be used as a dedicated portion, and an increase in the water content of the recovered oil due to the inflowing oil water at that portion can be prevented.

In the above-described embodiment, the case where the oil collecting tank 20 is a floating type floating tank has been described. However, this is merely an example, and the present invention is not limited to this.

In the modification of FIG. 3, a tank chamber 33 is provided on the side wall of the sedation tank via an opening 31, and a gate 32 which can be lifted and lowered from below in the tank chamber is provided at the opening 31 so that the opening level is variable. To pump
21 oil collection tanks are arranged.

In the modification of FIG. 4, the oil collecting tank 40 is not a floating type, but is mounted on a column 41 installed vertically along the wall of the sedation tank.
40 is supported so that the height position can be adjusted.

Other modifications are also possible. For example, the oil collecting tank may be arranged in a plurality of calming tanks, and the external shape of the oil collecting tank is not limited to a circular shape, but may be various rectangular shapes.

[Effects of the Invention] As described above, the oil-water separator of the present invention employs a unique circulation system, so that it can effectively cope with a change in the inflow of the water to be treated. Since the unit structure is relatively simple and installation does not take much time, it is suitable as an economic oil-water separation device for oil-containing sewage in business facilities where rainwater may be mixed, such as a gas station. It can be constructed in a short period of time with a relatively small equipment area due to the construction.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing an oil-water separator according to a preferred embodiment of the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 and 4 are partial schematic sectional views showing modified examples. (Explanation of symbols of main parts) 1: unit, 10: receiving tank, 11: first sedation tank, 12: second sedation tank, 13: third sedation tank, 14: inspection tank, 20: oil collection tank, 21: Pump, 22: piping, 30: control panel.

Claims (10)

(57) [Claims] 1. An oil-water separation apparatus for separating and floating oil by passing water to be treated such as sewage mixed with oil through a plurality of water tanks arranged in series in a plurality of stages, comprising: a receiving tank for receiving the water to be treated from an upper opening; A plurality of stages of sedation tanks arranged in series from upstream to downstream for receiving and sequentially calming the water to be treated from the lower layer in the receiving tank, at least the surface layer of the water to be treated in the calming tank at the downstream end An oil collecting tank for mainly taking up floating oil as overflow, a circulating pump means for returning the oil water taken into the oil collecting tank to the receiving tank, and an oil separation-treated water from the bottom of the calming tank at the downstream end. An oil-water separation device, comprising: 2. The oil-water separator according to claim 1, wherein the sedation tank includes a pair of adjacent sedation tanks communicating with each other at a bottom. 3. The sedation tank includes a pair of adjacent sedation tanks communicating with each other at a bottom portion, and further includes another sedation tank connected with a downstream sedation tank of the adjacent sedation tanks at a surface portion. 2. The oil-water separation device according to 1. 4. The oil / water separator according to claim 1, wherein the receiving tank is connected to the sedation tank at the upstream end by a rising flow path immediately above the sludge reservoir at the bottom. 5. The oil / water separation device according to claim 1, wherein the capacity of the receiving tank is larger than that of each of the calming tanks. 6. A drive control for detecting the level of the surface oil water of the surface sedation tank of the downstream sedation tank overflowing into the oil collecting tank and maintaining the overflow of the circulating pump means so as to maintain the overflow. The oil-water separation device according to claim 1, further comprising a control unit that performs the operation. 7. The oil-water separation device according to claim 1, wherein the oil collecting tank includes an independent vessel arranged so that an upper edge thereof is slightly set below the surface of the water to be treated in the calming tank at the downstream end. . 8. The oil / water separation apparatus according to claim 7, wherein the independent vessel is suspended and supported in the water to be treated by the float principle. 9. The oil-water separator according to claim 7, wherein the independent container is supported by a column so that a height position of the upper edge can be adjusted. 10. The oil / water separator according to claim 7, wherein said circulation pump means includes a submersible pump disposed in said independent vessel.