JP2012096126A - Method and apparatus for treating car washing wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating car washing wastewater which can reduce decay and odor generation due to the washing wastewater.SOLUTION: The method and the apparatus for washing a car is characterized in that (a) a filter surface of a filtering device is coated with suspension of powdery diatomaceous earth to form a diatomaceous earth layer, (b) a surface of the diatomaceous earth layer is coated with suspension of powdery activated carbon to form an activated carbon layer, (c) the car washing wastewater is filtered through two filtration assistant layers thus formed by the above steps, (d) obtained liquid filtrate is sent to an ultraviolet sterilizer and is subjected to sterilization treatment, (e) washing water thus sterilized is used to wash the car and further (f) the car washing wastewater is circulated to the filtering device provided with the filter having the filtration assistant layers.

Description

  The present invention relates to a car wash drainage that is processed at a car wash drain containing machine oil, oil such as wax, mud, sand, surfactants, etc. generated by a car wash station by a filtration device using natural materials and reused as wash water. The present invention relates to a method for treating water and a car wash wastewater treatment apparatus that prevents generation of off-flavors from recycled water.

  With the growing interest in effective use of water resources, expectations for water reuse technology are growing. At car wash stations, a large amount of tap water is used, and the waste water is discharged into the sewers without being sufficiently treated. Therefore, there is a growing demand for water saving in car washing and concerns about water pollution.

  Then, the trial which tries to solve the said subject is made | formed by processing a car wash wastewater and reusing the treated water as car wash water. Known methods for car wash wastewater treatment include sand filtration devices, coagulation sedimentation treatment, biological treatment, ozone treatment, electrolysis treatment, hollow fiber membrane separation, and the like described in Patent Document 1. ing. However, in this method and apparatus, oil content such as machine oil and wax, mud, sand, car wash drainage including surface activity and the like can be removed by a filtration device. However, when cleaning water is circulated, microorganisms grow. There was a problem that the odor became strong.

  In addition, in the filtration device used in Patent Document 1, for example, a filter aid layer made of diatomaceous earth and activated carbon formed on the surface of a spring filter sticks to the filter surface during backwashing due to its adhesiveness and peels off. There was a problem that it was difficult.

JP 2009-101981

  Accordingly, an object of the present invention is to provide a car washing method and an apparatus thereof that can reduce sewage and environmental pollution caused by washing waste water.

  Another object of the present invention is to provide a method and apparatus for treating car wash wastewater that can reduce the occurrence of decay and odor due to car wash wastewater.

  Still another object of the present invention is to make effective use of car wash drainage containing oil (machine oil, pitch, wax, etc.), surfactant, earth and sand (soil, sand, etc.), etc. generated from a car wash device or car wash station. Another object of the present invention is to provide a car wash method and apparatus using water that has been highly treated and recycled.

  Another object of the present invention is to provide a car washing method and an apparatus therefor in which a filter aid layer formed on the filter surface does not adhere to the surface during backwashing.

  The above object is achieved by the following (1) to (8).

(1) (a) A suspension of powdered diatomaceous earth is coated on the filter surface of the filtration device to form a diatomaceous earth layer,
(B) coating the suspension of powdered activated carbon on the surface of the diatomaceous earth layer to form an activated carbon layer;
(C) Filtering car wash wastewater through the two-layer filter aid layer formed in this way,
(D) The filtrate obtained is sent to an ultraviolet sterilizer for sterilization,
(E) A car wash method characterized in that the washing liquid sterilized in this way is subjected to car washing, and (f) car washing waste liquid is circulated through a filtering device having a filter having the filter aid layer.

  (2) (g) The method according to (1) above, wherein a part of the sterilization washing liquid obtained in the step (d) is subjected to a photocatalytic sterilization treatment and then circulated to the ultraviolet sterilization apparatus.

  (3) The method according to (1) or (2) above, wherein the car wash wastewater is subjected to oil / water separation to remove oil and then sent to the step (c).

  (4) The method according to any one of (1) to (3), wherein when the filtration efficiency of the filter aid layer decreases, the filter aid layer is removed by a backwash method.

  (5) The method according to any one of (1) to (4), wherein the backwashing is performed by press-fitting compressed air from above.

  (6) The method according to (5), wherein the backwashing is performed by intermittently injecting compressed air from the inside of the filter in the presence of water outside the filter in the main filter.

(7) (a) a car wash wastewater separation tank;
(B) a suspension tank for dispersing at least one powdered diatomaceous earth and powdered activated carbon;
(C) a main filtration tank including a filter surface formed with the diatomaceous earth layer and a filter formed with an activated carbon layer on the surface of the diatomaceous earth layer;
(D) an ultraviolet sterilizer for storing and sterilizing the filtrate obtained in the main filtration tank;
(E) A car wash apparatus using the sterilized washing liquid.

  (8) (f) Furthermore, the apparatus as described in said (7) which provides the photocatalyst sterilizer for using a part of ultraviolet sterilization washing | cleaning liquid obtained at the said process (d) for a sterilization process.

  Since the present invention has the above-described configuration, it is possible to provide a car wash method and an apparatus thereof that are environmentally friendly and have an excellent car wash effect. Further, according to the present invention, since the cleaning liquid can be used in a circulating manner, it is possible to reduce contamination of sewage and the environment. Furthermore, according to the present invention, it is possible to prevent the generation of a strange odor by the car wash drainage. Further, according to the present invention, as the filter aid layer, a diatomaceous earth layer is provided on the filter side, and an activated carbon layer is provided thereon, so that the filter aid layer formed in this manner is easily peeled off during backwashing. . Furthermore, according to the present invention, the deodorizing effect is further improved by subjecting a part of the cleaning liquid that has not been used directly to the car sterilized by the ultraviolet sterilizer to the photocatalytic sterilization.

It is a flow sheet which shows the outline of one example of the car washing method and the device by the present invention. It is sectional drawing which shows the state before the filter aid adheres in the spring filter used in this invention. It is sectional drawing which shows the state before the filter aid adheres in the spring filter used in this invention. It is sectional drawing which shows the state before the filter aid adheres in the spring filter used in this invention. It is sectional drawing which shows the state at the time of backwashing of the spring filter used in this invention.

  Next, the present invention will be described in detail with reference to the drawings. That is, FIG. 1 is a flow sheet showing an outline of an embodiment of the car wash method and apparatus according to the present invention.

  The “car” to be cleaned according to the present invention refers to automobiles such as passenger cars, buses, trucks, etc., motorcycles such as motorcycles, trains, cars, etc. explain.

(1) Pretreatment process After the main solid content is settled and separated from the separation tank 1 for separating mud, sand, and other solid contents obtained from the car washing process, which will be described later, via the conduit 3 by the pump 2, The oil / water mixture 4 such as car wash wastewater is sent to a first pretreatment filter (solid content separator) 5 to further separate and remove the contained solid content and the like. The first pretreatment filter 5 may be of any type. For example, there are a bag filter and a pincushion type, and the mesh width (opening width) is 5 to 25 μm, preferably 10 to 10 μm. 25 μm. That is, if the thickness is less than 5 μm, clogging is quick, whereas if it exceeds 25 μm, the amount of leakage increases.

  Subsequently, the obtained filtrate is sent to the second pretreatment filter (oil-water separator) 7 through the conduit 6. For example, the filtrate is introduced from the lower part of the second pretreatment filter 7 by the lower nozzle 8 of the conduit 6, and enters the filter 7 while ascending in the second pretreatment filter 7. Oil components such as oil, surfactant, emulsion and the like are adsorbed and removed from a granular oil absorbent (not shown) filled, and the aqueous component 11 overflows 9 and is sent to the raw water tank 10.

  The second pretreatment filter 7 is filled with a granular oil absorbing material having an average equivalent diameter of 5 to 30 mm, preferably 10 to 20 mm, for example. There are various kinds of such granular oil-absorbing materials. For example, an inorganic continuous porous oil-absorbing ceramic obtained by firing clay or silica. There are various types of such oil-absorbing ceramics. For example, there is a Filton type FA-4 (trade name of Filton Co., Ltd.).

  When the adsorption saturation state is reached, it can be removed from the manhole 12 and replaced with a new one, and the saturated oil-absorbing ceramic can be regenerated by firing.

(2) Preparation of filter aid suspension Water, for example, tap water or treated water 14 is supplied to the first filter aid suspension tank 13 and diatomaceous earth is supplied from the first manhole 15. Then, it is suspended and dispersed with stirring by the stirrer 16, and then sent to the raw water tank 10 through the conduit 17. This suspension 13a is sent to the main filtration device 20 by its own weight, for example, through the pump 18 and the conduit 19, and is pre-coated on the surface of the filter as described later. The average particle diameter of the diatomaceous earth is 5 to 50 μm, preferably 20 to 40 μm. That is, diatomaceous earth with an average particle size of less than 5 μm may leak from the spring filter 28 as described later, while diatomaceous earth with an average particle size of more than 50 μm may be clogged.

  Next, when a predetermined amount of the diatomaceous earth as the filter aid is pre-coated and the operation is completed, water, for example, tap water or treated water, is supplied to the second filter aid suspension tank 23 via the conduit 22. At the same time, powdered activated carbon is supplied from the second manhole 24 and suspended and dispersed with stirring by the stirrer 25. Then, the suspension 23a is sent to the raw water tank 10 through the conduit 26 under its own weight, for example. . The average particle diameter of the powdered activated carbon is 100 to 500 μm, preferably 200 to 300 μm. That is, if the activated carbon is less than 100 μm, there is a risk of leakage from the spring filter 28, while if activated carbon having a particle diameter exceeding 500 μm, the coating on the spring filter may not be successful.

(3) Main filter Although there are various types of main filter 20, for example, there is a spring filter type, for example. As shown in FIG. 1, the spring filter 28 is schematically shown in FIG. 1. At least the liquid supplied into the container 27 passes through the filter wall formed by bridging the filter aid layer on the surface of the spring and enters the inside. The filtrate is discharged from one end.

  The coating of the filter aid in the spring filter type main filter 20 will be described with reference to FIGS. That is, FIG. 2 shows a state where no filter aid is attached. In a main filter 20 (not shown) that holds and holds at least one clean spring filter 28, for example, a suspension of diatomaceous earth is first supplied from the lower part, and a pump 18 and a conduit 19 are supplied from the raw water tank 10. When introduced as shown in FIG. 1, the diatomaceous earth suspension passes through the spring portion 28 and flows upward, and during that time, diatomaceous earth accumulates on the surface of the spring portion 28 due to bridging phenomenon, as shown in FIG. A first filtration membrane layer (diatomaceous earth layer) 29 is formed. Meanwhile, the filtrate after depositing diatomaceous earth is circulated to the raw water tank 10 via the conduit 31.

  When the first filtration membrane layer 29 reaches a predetermined thickness, the operation is stopped. The film thickness can be predicted by various methods. For example, when the amount of diatomaceous earth to be supplied to the spring filter 28 is stopped, the difference in the amount of diatomaceous earth is defined as the volume of the supply amount, and this is divided by the area of the spring filter portion. Thus, a thickness can be obtained.

  Next, similarly, the activated carbon suspension 23 a is sent from the lower part to the main filter 20 through the pump 18 and the conduit 19 from the raw water tank 10. The activated carbon suspension 23 a sent to the main filter 20 passes through the surface of the diatomaceous earth layer 29 of the spring filter 28, and the filtrate is circulated through the conduit 31 to the raw water tank 10. Meanwhile, the activated carbon is deposited on the surface of the diatomaceous earth layer 29 to form the activated carbon layer 30 as shown in FIG. The activated carbon layer 30 has the same thickness as that of the diatomaceous earth layer. Moreover, if the measurement of such thickness is repeated, it can be measured over time according to an empirical rule.

  The thickness of the diatomaceous earth layer 29 is 0.5 to 1 mm, preferably 0.5 to 0.7 mm, and the thickness of the activated carbon layer 30 is 0.3 to 0.7 mm, preferably 0.3 to 0.4 mm. is there. That is, when the thickness of the diatomaceous earth layer 29 is less than 0.5 mm, the thickness is thin and thus filtration is insufficient. On the other hand, when the thickness exceeds 1 mm, the filtration is insufficient.

  Further, if the thickness of the activated carbon layer 30 is less than 0.3 mm, filtration is insufficient, while if it exceeds 0.7 mm, backwashing is insufficient and running cost increases. Furthermore, the thickness ratio between the diatomaceous earth layer 29 and the activated carbon layer 30 is 6: 4 to 8: 3, preferably 7: 3 to 2: 1, of the activated carbon layer 3 with respect to the thickness of the diatomaceous earth 29. That is, when the thickness of the activated carbon layer 30 is less than 8: 3, the detergent cannot be removed and the film is not transparent. On the other hand, when the thickness exceeds 6: 4, clogging is likely to occur and backwashing is difficult. .

(4) Prevention of peeling of filter aid layer When the double filter aid layer composed of the diatomaceous earth layer 29 and the activated carbon layer 30 is formed as shown in FIG. 4, the circulation of the activated carbon suspension 23a is stopped. Next, the aqueous component 11 in the raw water tank 10 is supplied to the main filter 20 via the pump 18 and the conduit 19. The supplied aqueous component 11 passes through the double filter aid layers 29 and 30 of the spring filter in the main filter 20, and oil and other components are separated by filtration and through a conduit 32, which will be described later. It is sent to the safety filter 33 through the device (treated water tank) 37. In this case, if the treated water tank becomes full, the valve 60 closes and the filtered water may be stopped. In this case, the filter aid layer may be peeled off by a reverse pressure. Therefore, it is preferable to circulate the filtered water to the raw water tank 10 through the conduit 31 in preparation for the stop of the filtered water. Alternatively, it is desirable to always circulate a part of the main filter 20 to the raw water tank 10 when the main filter 20 is operated.

(5) Backwashing of the main filter When impurities are sufficiently removed by the filter aid layers 29 and 30 of the main filter 20 and the filtration capacity is lowered, the operation of the pump 18 is stopped and the backwashing operation is started. .

  As shown in FIG. 1, this backwashing is performed by sending compressed air from the compressor 34 through the conduit 35 through the conduit 35 and cleaning from the outside of the spring filter 28, and switching back to send compressed air through the conduit 36 to the inside of the spring filter 28. Further cleaning is performed (see FIG. 5). The separated filter aid such as diatomaceous earth is discharged from the conduit 37 and received in the sludge receiving tank 42, and its moisture is sent to the separation tank 1 by the conduit 38, while the solid content is removed from the system through the discharge port 39. The Air is discharged out of the system through the discharge port 40, while the liquid is received in the sludge receiving tank 42 through the conduit 41.

  In addition, the aqueous component (filtrate) separated by the main filter 20 may be sent directly to the ultraviolet sterilizer (processing tank) 37. However, since there is a possibility that solid content or the like may be mixed, the first safety A filter 33 may be used.

  There are various types of the first safety filter 33. For example, the first safety filter 33 is a back filter type, and the mesh (opening interval) is 0.22 to 10 μm, preferably 0.5 to 5 μm. It is.

(6) Ultraviolet sterilizer (treated water tank)
The filtrate discharged from the first safety filter 33 is sent to an ultraviolet sterilizer (processing tank) 37 through a conduit 34. The ultraviolet sterilizer 37 is provided with at least one ultraviolet sterilization lamp 37a, 37b, for example. The cleaning liquid 42 sterilized by the first ultraviolet sterilizer 37 is sent to the cleaning liquid tank 45 through the pump 43 and the conduit 44. Further, a part of the cleaning liquid 42 is sent to the photocatalyst sterilizer 47 via a conduit 46 if necessary.

(7) Photocatalyst sterilizer This photocatalyst sterilizer 47 is formed by coating a photocatalyst titanium apatite thin film on its inner surface, coating it with glass particles, or adsorbing it on a porous ceramic, or a combination thereof. The ultraviolet sterilization lamp 48 is provided in the container. That is, for example, a photocatalyst having a chemical structure in which a part of Ca of calcium hydroxyapatite is substituted with Ti as described in Japanese Patent No. 3,928,596 is kneaded directly with a resin material as required in a container. The resin composition is coated.

  The cleaning liquid sterilized here is further filtered by the second safety filter 49 as necessary, and then sent to the ultraviolet sterilizer (treated water tank) 37. The reason why the treated water is sterilized by the ultraviolet sterilizer (treated water tank) 37 is that if the circulation of the treatment liquid is repeated, the growth of miscellaneous bacteria disappears and the odor disappears. Similarly, the second sterilizer 47 is also for preventing the growth of various germs and the generation of odor. In the second safety filter 49, particulate matter is filtered out in an emergency.

  A part of the washing liquid is further used as backwash water when washing the main filtration device 20 through the conduits 62, 36 and 32 (see FIG. 5). At the same time, compressed air is introduced from the conduit 51.

(8) Cleaning Liquid Tank The cleaning liquid 42 obtained by the ultraviolet sterilizer 37 is sent to the cleaning liquid tank 45 through the pump 43 and the conduit 44. Again, if necessary, an ultraviolet germicidal lamp 52 is used to prevent the growth of germs and the generation of odors in the cleaning liquid. When the use of the car wash machine increases and the amount of water becomes insufficient, the cleaning liquid tank 45 is supplied with water, for example, tap water, through the conduit 53.

(9) Car Wash The cleaning liquid 42 is sent to the car wash machine 56 via the pump 54 and the conduit 55 and used for washing the automobile 57. The car wash drainage is collected on the car wash drainage collection floor 58 and then circulated through the conduit 59 to the separation tank 1.

  The cleaning liquid 42 obtained by the ultraviolet sterilizer 37 is not circulated to the photocatalyst sterilizer 47, but is sent to the main filtration tank 20 along with the compressed air supplied from the conduit 51 through the conduits 62, 36, and 32. It may be used for backwashing.

(10) Backwashing of the main filter When the filtration efficiency of the main filter 20 is reduced, the pump 18 is stopped and the supply of the aqueous component 11 in the raw water tank 10 is stopped. Subsequently, the filter aid layer formed on the surface of the spring filter is peeled off by press-fitting compressed air into the spring filter 28 through the conduit 36 from the pump 34. In this case, in the state where water is present outside the spring filter, the compressed air is repeatedly injected and stopped for 1.5 seconds, thereby eliminating air escape due to partial separation of the filter aid and uniform separation. It becomes possible.

  Next, the present invention will be described in more detail with reference to examples.

Example In the car wash apparatus shown in FIG. 1, the car wash wastewater after washing the automobile 57 was collected in the separation tank 1 from the car wash wastewater collection floor 58 via the conduit 59. Here, the oil-water mixture 4 in which the solid content is settled and the supernatant liquid is overflowed and the above operation is repeated to the next tank to substantially remove the solid content from the last tank is passed through the pump 2 and the conduit 3 to form a mesh. It was sent to the first pretreatment filter 5 having an opening of 10 μm and subjected to filtration to remove solids having an average particle diameter larger than 10 μm. Subsequently, this filtrate was sent to the second pretreatment filter 7 via the conduit 6.

  This second pretreatment filter 7 is filled with porous oil-absorbing ceramics (Filton FA-4, trade name of Filton Co., Ltd.) having an average equivalent diameter of 10 to 20 mm, and in the oil-water mixture supplied from the lower part. The oil was removed by adsorption.

  Meanwhile, tap water 14 is supplied to the first filter aid suspension tank 13 and 4,200 g of diatomaceous earth (average particle size 20 to 40 μm, 600H manufactured by Chuo Silica Co., Ltd.) is supplied from the first manhole 15. Then, it was suspended and dispersed with stirring by a stirrer 16 and then sent to the raw water tank 10 via a conduit 17. This diatomaceous earth suspension 13a was sent 30 times through a pump 18 and a conduit 19 to a main filter 20 having 30 spring filters 28.

  In this way, the state shown in FIG. 2 is changed to the state shown in FIG. 3, and diatomaceous earth adheres to the surface of the spring filter 28 of the main filter by bridging to form a diatomaceous earth tank 29. The filtrate is a spring filter. After moving to the inside 28, it was circulated from the conduit 31 to the raw water tank 10. The operation was stopped when the thickness of the diatomaceous earth layer reached about 0.5 mm.

  Next, the tap water 14 is supplied to the second filter aid suspension tank 23, and activated carbon powder (PK-D, manufactured by Kuraray Chemical Co., Ltd.) 2, having an average particle diameter of 0.25 mm from the second manhole. 100 g was supplied, suspended and dispersed with stirring by a stirrer 25, and then sent to the raw water tank 10 through a conduit 26. This activated carbon suspension was then sent to main filter 20 via pump 18 and conduit 19.

  Thus, as shown in FIG. 4, the activated carbon layer 30 is formed on the diatomaceous earth layer 29, and the filtrate is transferred to the raw water tank 10 through the conduit 31 after moving into the spring filter 28 in the same manner as described above. . The operation was stopped when the thickness of the activated carbon layer became 0.3 mm.

  Next, the aqueous component 11 in the raw water tank 10 overflowing from the second pretreatment filter 7 is supplied to the main filter 20 via the pump 18 and the conduit 18 and filtered, or at the time of coating and one of them. The part was circulated to the raw water tank 10 by a conduit 31. The oil and other components were removed by this filtration and sent to the safety filter 33 via the conduit 32. After 60 minutes, the filtration capacity of the main filter 20 was reduced, so the operation of the pump 18 was stopped and backwashing was performed. The filter aid of diatomaceous earth separated by the backwash operation was received by the sludge receiving tank 42 from the conduit 37, and only the water after solid-liquid separation was sent to the separating tank 1 by the conduit 38.

  The filtrate was sent to an ultraviolet sterilizer (treated water tank) 37 through a conduit 34 and subjected to sterilization by two 40-watt ultraviolet sterilization lamps. The cleaning liquid 42 sterilized here was sent to the cleaning liquid tank 45 via the pump 43 and the conduit 44. Here again, if necessary, sterilization was performed using the ultraviolet sterilization lamp 52, and then the automobile 57 was cleaned through the car wash machine 56. The washing liquid was sent to the separation tank 1 through a conduit 59.

  A part of the cleaning liquid 42 was sent to the photocatalyst sterilizer 47 via the conduit 46 and sterilized, and then circulated to the ultraviolet sterilizer 37 via the safety filter 49 as necessary.

  The state of treated water in each step in the above experimental operation was as shown in Table 1. In addition, each location is a position shown in FIG.

1 ... separation tank,
5 ... First pretreatment filter,
7: Second pretreatment filter,
10 ... Raw water tank,
13, 23 ... suspension tank,
20 ... Main filter,
37 ... UV sterilizer,
45 ... Cleaning liquid tank,
47 ... Photocatalyst sterilizer,
56 ... Car wash machine,
57 ... car,
58: Car wash drainage collection floor.

Claims (8)

(A) A suspension of powdered diatomaceous earth is coated on the filter surface of the filtration device to form a diatomaceous earth layer,
(B) coating the suspension of powdered activated carbon on the surface of the diatomaceous earth layer to form an activated carbon layer;
(C) Filtering car wash wastewater through the two-layer filter aid layer formed in this way,
(D) The filtrate obtained is sent to an ultraviolet sterilizer for sterilization,
(E) A car wash method characterized in that the washing liquid sterilized in this way is subjected to car washing, and (f) car washing waste liquid is circulated through a filtering device having a filter having the filter aid layer.   (G) The method according to claim 1, wherein a part of the sterilization washing liquid obtained in the step (d) is subjected to a photocatalytic sterilization treatment and then circulated to the ultraviolet sterilization apparatus.   The method according to claim 1 or 2, wherein the car wash wastewater is subjected to oil-water separation to remove oil and then sent to step (c).   The method according to any one of claims 1 to 3, wherein when the filtration efficiency of the filter aid layer is reduced, the filter aid layer is removed by backwashing.   The method according to any one of claims 1 to 4, wherein the backwashing is performed by press-fitting compressed air from above.   6. The method according to claim 5, wherein the backwashing is performed by intermittently injecting compressed air from the inside of the filter in the presence of water outside the filter in the main filter. (A) a car wash wastewater separation tank;
(B) a suspension tank for dispersing at least one powdered diatomaceous earth and powdered activated carbon;
(C) a main filtration tank including a filter surface formed with the diatomaceous earth layer and a filter formed with an activated carbon layer on the surface of the diatomaceous earth layer;
(D) an ultraviolet sterilizer for storing and sterilizing the filtrate obtained in the main filtration tank;
(E) A car wash apparatus using the sterilized washing liquid.   (F) Furthermore, the apparatus of Claim 7 which provides the photocatalyst sterilizer for providing a part of ultraviolet sterilization washing | cleaning liquid obtained at the said process (d) to a sterilization process.

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