JPH02222797A - Oil-water treatment apparatus - Google Patents

Abstract

PURPOSE:To reduce the running cost by providing an oil-water separation vessel and a sedimentation basin where sludge-water is separated into clear water and sludge. CONSTITUTION:In the oil-water separation vessel 1, floating-up oil is separated and discharged, and settleable materials, such as solids, are settled on the bottom part of the oil-water separation vessel 1. Emulsified waste liquid is mixed with the waste water and entered into a reaction vessel 2 through a communication pipe 4. In the reaction vessel 2, flocculant is added, and the emulsified liquid is flocculated and passed through nonwoven fabric layer from the clearances between the tapered surface of lower end of filter medium layer 6 together with the bubbles scattered through aeration pipes 5. The floating-up flocs are pressed, mixed agitated and passed through the filter medium layer 6 while exfoliating activated sludge, etc., sticking to the nonwoven fabric layer. The floating-up scum is entered into a sedimentation basin 3 through a communication pipe 13. By this method, the matters to be floated up are stably floated up.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is a method for physically treating domestic wastewater and gray water discharged from general houses, apartment complexes, high-rise buildings, etc., commercial wastewater from the food service industry, restaurants, etc. The present invention relates to a device for bioadsorption and decomposition treatment, particularly to a device for separating and treating oily water in wastewater.

[Conventional technology]

Conventionally, domestic wastewater, gray water, and business wastewater are clean water that is physically and chemically mixed or combined with organic and inorganic substances, and if such wastewater is released into the natural world as it is, it cannot be decomposed and purified by natural purification alone. However, it is known that the concentration exceeds the natural cycle, causing adverse effects.

Therefore, various wastewater treatment methods have been developed to prevent pollution caused by these wastewaters and purify the environment. In other words, the physical processing method is solid-liquid separation.

There are filtration methods and adsorption methods, and the biological treatment method is the domestic sludge method.The domestic sludge method is effective in terms of equipment miniaturization, simplicity, economic efficiency, and especially the small amount of surplus products, and the activated sludge method has become the mainstream wastewater treatment method. With this method, wastewater generated from normal daily life and business activities, excluding special hazardous substances, is easily bioadsorbed and decomposed by aerobic and anaerobic organisms, and converted into inorganic substances such as Co, H, and O. and returned to the natural world.

Here, a pressurized flotation method as shown in FIG. 4 is known as an activated sludge method. In other words, wastewater is contaminated by physical treatments such as screening, sedimentation, and flotation.

After separating and removing floating matter, free oil, etc.

! Flowed into tank 1111 (2nd plant), homogenized water quality, pH
1 liter, etc., and then the waste water stored in the adjustment tank (21) is sent to the pressurized flotation tank (22). Here, a polymer flocculant is added from the dissolution tank (23), pressurized air is sent to the pressurized flotation tank (22) by a pressure pump, the waste is floated together with air bubbles, and a certain amount of it is continuously aerated. Tank (24)
send to The wastewater that has entered the aeration tank (24) is aerated and mixed with activated sludge for a certain period of time, and organic matter is oxidized and decomposed. Also, at this time, pollutants such as fine earth and sand are adsorbed by the sludge.

The mixed liquid of sludge and treated water in the aeration tank (24) is then guided by natural flow to the settling tank (25). Here, the mixed liquid is allowed to stagnate and the sludge is separated by sedimentation. After the oil and flocculant are separated as a supernatant liquid, the treated water is discharged. This activated sludge treatment process removes over 95% of BOD from wastewater.

[Problem to be solved by the invention]

However, in the above-mentioned pressurized flotation method, the equipment is large, so a large installation area must be taken, and the residence time is 2.
It took a long time, up to 3 hours, and the running cost was high.

In addition, in the device using the above pressure flotation method, the pressure flotation tank (
22), the wastewater is treated with a coagulant in advance to remove some organic substances and lower the BOD.

Since activated sludge treatment is performed in the aeration layer (24), a pressurized flotation tank (22) and an aeration tank (24) are required.

In particular, sewage standards have recently become stricter, and wastewater from the restaurant industry, etc., where business wastewater is more than 50 ppm, is likely to be regulated to an oil content of 30 ppm or less based on normal hexane as an extractant, making countermeasures urgently needed.

In view of the above circumstances, the present invention is directed to domestic wastewater and gray water.

In particular, it is possible to clear the above regulatory values in a short time and at a low cost by performing physical and bioadsorption decomposition treatment of business wastewater, and above all, separating the emulsified oil in the wastewater by converting the two-stage treatment process into one. The challenge is to make this happen.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a reaction system equipped with an oil-water separation tank that separates raw water into floating oil and sedimentary substances, a nonwoven filter medium, an aeration pipe that supplies oxygen to the filter medium, and a flocculant injection device. An oil water treatment device consisting of a tank and a settling tank that separates 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 nonwoven fabric layers in the vertical direction, and the lower end of each nonwoven fabric layer is attached with an adhesive. It is constructed into a concentrated oil-water separator.

[For production]

By configuring the present invention as described above, first, X water is separated into floating oil and settling substances in an oil-water separation tank, and the supernatant oil is separated and extracted, and Ii! ! Shape substance form substance. Next, the waste water containing the emulsified oil liquid is sent to a reaction tank. In the reaction tank, a flocculant is added, and the emulsified oil liquid is surrounded by the flocculant and coagulates, and is separated from a plurality of vertically laminated nonwoven fabric layers. The sludge that has adhered to the surface of the filter medium is washed away as it passes through the non-woven fabric layer from the bottom of the filter medium along with air bubbles from the aeration pipe, pressurizes the air bubbles, and passes through the narrow filter bed to be mixed and stirred. surface. The floating oil flocs flow into the settling tank together with the sludge, and the sludge settles in the settling tank.
The 1iJ+ aggregate floats to the surface of the settling tank. The oil agglomerates in the supernatant that float to the surface are separated and the treated water is discharged. On the other hand, the sludge that has settled at the bottom of the settling tank is continuously returned to the oil-water separation tank and mixed with newly inflowing wastewater.

〔Example〕

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

The oil-water separator consists of an oil-water separation tank (1), a reaction tank (2), and a settling tank (3). Raw wastewater flows into the oil-water separation tank (1), and due to the difference in specific gravity, the raw wastewater is separated into buoyant components and sedimentary substances. Separate into two parts. A communication pipe (4) is provided between the oil-water separation tank (1) and the reaction tank (2), and the waste water is transferred between the two tanks to the oil-water separation tank (1).
) to the reaction tank (2). At the bottom of the reaction tank (2) is an aeration pipe (5) that supplies air and diffuses air bubbles into the liquid.
Place. In addition, a large number of filtering material layers (6) are installed in the reaction tank (2) so as to be perpendicular to the direction in which the wastewater passes. The J filter material layer (6) is made of, for example, a nonwoven fabric with synthetic fibers intertwined with each other, and as shown in FIG. Insert the stainless steel wire (7) parallel to the edge direction. Then, the torn edges of the filter material layer (6) are gathered together, and as shown in Fig. 2 (b)
The wire (7) is solidified with a synthetic resin adhesive (8) so that the edges are tapered on both sides as shown in FIG. Stainless steel wire (7) as shown in Figure 3
Insert both ends of the reaction +a (2) into the recessed holes (io) on the window surface (9) on the opposite wall surface and fix.

On the other hand, a flocculant injection device (11) is installed above the reaction tank (2).
, connect the outflow pipe (12) to the flocculant injection device (11), and connect the end of the outflow pipe (12) above the communication pipe (4) between the oil-water separation tank (1) and the reaction +6 (2). Sedimentation A (3) is installed in parallel on the downstream side of the 0 reaction tank (2) facing the water, and a connecting pipe (13) is installed between the reaction tank (2) and the sedimentation tank (3) to prevent overflow. is discharged to the sedimentation tank (3). A pump (14) is installed at the bottom of the settling basin (3), and a communicating pipe (15) is connected to the pump (14) and extended above the oil-water separation tank (1). A part of the sludge settled in the settling tank (3) is returned to the oil/water separation tank (1).

The operation of an example of oil/water separation processing will be explained.

The wastewater from the chamber Dx flows into the oil/water separation tank (1) at a rate of 20 liters/day. In the oil/water separation tank (1), oils and fats with low specific gravity float to the liquid surface, so the floating oils and fats are periodically separated and discharged.

On the other hand, sedimentary substances such as solids settle to the bottom of the oil/water separation tank (1). On the other hand, the emulsified wastewater containing emulsified oils and fats is mixed with the wastewater and flows through the communication pipe (4) to the reaction tank (39).
flows into.

In the reaction tank (2), the flocculant from the flocculant injection device (11) is added, and the emulsion is flocculated together with air bubbles diffused by the air diffuser (5) between the tapered surfaces of the lower edge of the filter layer (6). It passes through the nonwoven fabric layer through the gaps. At this time, when passing through the gap in the filter material layer (6), the floating oil aggregates are pressurized and mixed and agitated to peel off the activated sludge and filter membrane adhering to the nonwoven fabric layer and to form the filter material layer (6). pass. These floating scum then rise in a stable manner. The floated scum flows into the settling tank (3) via the communication pipe (13).

The sludge from Fang Shaohuang settles to the bottom of the reaction tank, but floats up together with air bubbles, is decomposed and purified by the activated sludge of the filter medium NJ (6), and flows into the settling tank (3) together with the scum. Among the inflowing wastewater, sludge settles to the bottom of the settling tank (3),
The oil flocs float to the surface of the drainage tank (3). The supernatant of the agglomerated oil that has surfaced is separated and discharged, and the clarified treated water is discharged. Further, the sludge settled at the bottom of the settling tank (3) is sucked by the pump (14) and returned to the oil-water separation tank (1) via the communication W (15).

〔Effect of the invention〕

Since the present invention has the above configuration, it has the following effects.

(1) The oil flocs flocculated by the flocculant mix and stir the waste water and air, pass through the narrow space of the non-woven filter bed, and float together with compressed air bubbles, creating a pressurizing effect and can be washed.

(2) Floating objects (scum) can be floated in a stable manner in a short reaction time.

(3) Since biodegradation occurs through a filter bed, less scum is generated, and treatment can be carried out in a short time with simple aeration.

(4) Since the lower end of the filter medium is bound with an adhesive, the oil aggregates floating together with air bubbles are not blocked in the filter medium and can pass through the filter medium one after another.

The following shows the cheetah whose wastewater was treated with the device of this example. Raw wastewater BOD loooppm raw wastewater COD 800ppm raw wastewater normal hexane value 200 ppu + suspended matter value (SS value) 500ppm coagulant concentration 2% of raw wastewater PH
6,0~8.0 Final BOD 300ppm or less Final COD 300ppm or less Final normal hexane value 3Qppm or more Final SS
Value 100ppii or less Final PH6
,i~8,0 In this way, BOD removal rate is 50% with treatment residence time of 50 minutes.
, the n-hexane removal rate was 90%.

Although the device of the present invention has been described as being for separating oil and water discharged from a cellar, it can also be used to separate raw wastewater discharged from general buildings, such as gray water and urine wastewater, which have been treated by the sedimentation method, activated sludge method, aeration method, etc. It is also effective for processing, etc.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an oil-water separator according to an embodiment of the present invention, and Fig. 2 (a) shows a state in which the edge of the filter layer made of non-woven fabric is torn before inserting the stainless steel wire from the edge. Figure 2 (b) is a side view of the edge of the filter material layer solidified with synthetic resin adhesive, Figure 3 is a perspective view showing part of the wall of the reaction tank, Figure 4 is the conventional 1 is a schematic diagram of a sewage treatment device using a pressure flotation method. (1)...Oil-water separation tank (2)...Reaction tank (3)...
Sedimentation tank (5)・Diffuser pipe (6)...filter material N
(7)... Stainless steel wire (8)... Synthetic resin adhesive (11)... Coagulant injection device

Claims (2)

[Claims] (1) A reaction tank equipped with an oil-water separation tank that separates raw water into floating oil and sedimentary substances, a non-woven filter medium, an aeration pipe that supplies oxygen to the filter medium, and a flocculant injection device, and an oil-water separation tank that separates raw water into floating oil and sedimentary substances; An oil water treatment device characterized by comprising a settling tank that separates sludge water into fresh water and sludge. (2) The oil and water treatment apparatus according to claim (1), wherein the filter medium is formed by laminating a plurality of nonwoven fabric layers in the vertical direction, and the lower end of each nonwoven fabric layer is bound together with an adhesive.