JP3896101B2 - Car wash wastewater treatment equipment - Google Patents

Description

  The present invention relates to a car wash wastewater treatment apparatus capable of obtaining a high water treatment effect in a narrower installation space.

  Along with increasing interest in effective use of water resources, demand for water saving for washing water such as car wash stations that consume a large amount of tap water (150L or more per vehicle is required), while water quality for draining water as it is Concerns about pollution are growing. In particular, the wastewater generated at the car wash station contains not only oil such as wax but also surfactant as well as earth and sand. Surfactants are not easily decomposed naturally, leading to environmental pollution of rivers and lakes. Then, the trial which tries to solve the said subject is made | formed by processing car wash wastewater and reusing treated water as car wash water.

As a treatment method for car washing wastewater and the like, in addition to methods such as sand filtration treatment, coagulation precipitation treatment, ozone treatment, etc., a car wash by filtration equipped with a filter using a hollow fiber membrane disclosed in JP 2000-127913 A Although a system is known, in any of the methods, there is a problem that the apparatus is large, it is necessary to secure a wide installation place, and the processing cost becomes high. In particular, regarding the securing of the installation location, since there are various spaces in the car wash, there is a demand for a wastewater treatment apparatus that can be applied without reducing the treatment capacity even in a narrow space.
JP 2000-127913 A Japanese Patent Application No. 2002-108767

  The present invention is a car wash wastewater treatment device that is installed in a car wash station of a vehicle such as a gas station and used for the treatment of car wash wastewater, and in a limited installation space (installation area and installation volume) depending on the installation location. It is an object of the present invention to provide a car wash wastewater treatment apparatus capable of obtaining a high water treatment effect.

The present invention is a car wash wastewater treatment apparatus having at least a coagulation-precipitation treatment unit using a coagulant, a membrane treatment unit, and an activated carbon treatment unit as means for solving the problem,
The planar area of the entire apparatus is 1 to 5 m ² , the maximum height is 1.5 to 2.5 m, and the ratio of the planar area of each part to the planar area of the entire apparatus is 25 to 55% for the coagulation sedimentation processing part, the membrane processing part Is 2 to 10%, the activated carbon treatment part is 1 to 10%, and a car wash wastewater treatment device having a COD removal rate of 30% or more obtained from the following formula is provided.

COD removal rate (%) = (COD of car wash wastewater-COD of treated water) / COD of car wash wastewater x 100
Further, the present invention is a car wash wastewater treatment apparatus having at least a coagulation-precipitation treatment unit using a coagulant, a membrane treatment unit, and an activated carbon treatment unit as another means for solving the problem,
The planar area of the entire apparatus is 1 to 5 m ² , the maximum height is 1.5 to 2.5 m, and the ratio of the planar area of each part to the planar area of the entire apparatus is 25 to 55% for the coagulation sedimentation processing part, the membrane processing part Is 2 to 10%, the activated carbon treatment part is 1 to 10%, and a car wash wastewater treatment apparatus having a treatment rate per apparatus unit volume determined from the following formula of 0.25 to 0.65 (1 / hr) is provided.

Processing speed per unit volume (1 / hr) = Processing speed (m ³ / hr) / Device volume (m ³ )
The car wash wastewater treatment apparatus of the present invention may be composed only of a coagulation sedimentation treatment unit, a membrane treatment unit, and an activated carbon treatment unit. In addition, the total proportion of the planar area of the coagulation sedimentation processing unit, the membrane processing unit and the activated carbon processing unit occupying the planar area of the entire apparatus is not 100%. This is because an accessory element including a connecting means such as a pipe connecting each processing unit is necessary. In addition, COD in this invention is measured by the method as described in an Example.

  The car wash wastewater treatment apparatus of the present invention can obtain a high water treatment effect while making the size of the entire apparatus more compact. For this reason, it can be installed in a narrow installation space (installation area and installation volume), and effects such as protection of water resources by reuse of washing wastewater and reduction of load on sewage treatment facilities by reduction of total wastewater can be obtained. .

  The car wash wastewater treatment apparatus of the present invention has at least a coagulation / precipitation treatment unit using a flocculant, a membrane treatment unit, and an activated carbon treatment unit, and further adds other wastewater treatment means within a range that satisfies the following requirements. can do.

Area of the plane of the entire car wash wastewater treatment unit is 1 to 5 m ^2, preferably 2.0~4.5m ^2, the maximum height of the car wash wastewater treatment apparatus is 1.5～2.5M, preferably 1.8~2.2m is there. When the device is a cube or a rectangular parallelepiped, the maximum height of the device matches the height of the device.

  The occupation ratio (hereinafter referred to as “occupation ratio of the coagulation sedimentation processing portion”) with respect to the planar area of the entire apparatus of the coagulation sedimentation processing portion is 25 to 55%, preferably 30 to 50%. The agglomeration sedimentation processing unit has a function of adding a flocculant to the water to be treated (car wash wastewater), a sedimentation treatment of the agglomeration treatment liquid, and a supernatant storage function, and consists of one tank or two or more tanks. Can be a thing. When the coagulation sedimentation processing part consists of two or more tanks, the occupation ratio is determined by the total plane area of all the tanks.

  The occupation ratio (hereinafter referred to as “occupation ratio of the film processing unit”) with respect to the planar area of the entire apparatus of the film processing unit is 2 to 10%, preferably 3 to 8%. The membrane treatment part is usually a container in which a separation membrane is accommodated in a case or tank, and the planar area of the membrane treatment part means the planar area of the separation membrane excluding the container. .

  The occupation ratio (hereinafter referred to as “occupation ratio of the activated carbon treatment section”) of the activated carbon treatment section with respect to the planar area of the entire apparatus is 1 to 10%, preferably 2 to 8%. The activated carbon treatment part is usually a container in which activated carbon is filled, and the planar area of the activated carbon treatment part means the planar area of the activated carbon excluding the container.

  In this invention, the COD removal rate calculated | required from a following formula is 30% or more, Preferably it is 40% or more, More preferably, it is 50% or more.

COD removal rate (%) = (COD of car wash wastewater-COD of treated water) / COD of car wash wastewater x 100
In the present invention, the processing rate per unit volume of the apparatus determined from the following formula is 0.25 to 0.65 (1 / hr), preferably 0.3 to 0.60 (1 / hr), more preferably 0.4 to 0.55 (1 / hr). It is.

Processing speed per unit volume (1 / hr) = Processing speed (m ³ / hr) / Device volume (m ³ )
As described above, the car wash wastewater treatment apparatus of the present invention can be installed in a limited installation space (installation area and installation volume) by setting the planar area of the entire apparatus and the maximum height of the apparatus within a predetermined range. In addition, by controlling the manufacturing area and the operating cost by making the occupation area of the plane of each processing unit within a predetermined range, a high water treatment effect [COD removal rate of 30% or more, processing per unit unit volume The speed is 0.25 to 0.65 (1 / hr).

  Hereinafter, an embodiment of a water treatment system including the car wash wastewater treatment apparatus of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram of a wastewater treatment apparatus suitable for a cross flow filtration method. The apparatus of the present invention may be a car wash wastewater treatment apparatus suitable for the dead end filtration method.

  The car wash wastewater treatment apparatus of the present invention includes a coagulation sedimentation treatment unit 2, a membrane separation unit 3, and an activated carbon treatment unit 4, which are connected by a pipe or the like, as shown in FIG. It may include components necessary for the treatment of wastewater not shown in FIG. In FIG. 1, P is a pump, P1 to P4 are pressure gauges, F1 to F2 are flow meters, MV is a flow rate adjustment valve, and all the opening and closing valves are the same display. In addition, FIG. 1 shows each component, the connection state of each component, and the wastewater treatment flow, and does not indicate the arrangement state of each component or the size (planar area and volume) of the entire apparatus. .

  Drainage containing oil and surfactant generated at a car wash or the like is normally stored in an oil / water separation tank 20 (not included in the apparatus of the present invention) installed in the car wash or the like through a drain pit. . The oil / water separation tank 20 may collect rainwater, detergent for cleaning the floor of the facility, drainage mixed with oil, and the like. The oil / water separation tank 20 is composed of a total of four sedimentation tanks as shown in the figure. The oil / water separation tank 20 precipitates in order from suspended particles (SS) of large particles such as gravel, and pumps the waste water from the final sedimentation tank by a pump. The raw water storage tank 1 is sent to store water. This is the raw water for treatment. In the sedimentation tank into which the drainage of the oil / water separation tank 20 flows, a filter net (made of a wire net or the like) as shown in the figure can be installed in order to remove large foreign matters such as gravel.

  Next, the raw water in the raw water storage tank 1 is sent to the coagulation sedimentation processing unit 2. At this time, wastewater may be sent directly from the oil / water separation tank 20 to the coagulation / sedimentation processing unit 2, and if the wastewater is small in volume, sand, mud, etc., without using the oil / water separation tank 20, The waste water may be sent directly to the coagulation sedimentation processing unit 2. The raw water storage tank 1 may be included in the apparatus of the present invention or may be separate from the apparatus of the present invention depending on the amount of car wash drainage, the installation location, and the like. For example, if the amount of drainage per unit time is small and the installation location of the raw water storage tank 1 cannot be secured, the raw water storage tank 1 can be incorporated into the apparatus of the present invention.

  In the coagulation sedimentation processing unit 2, a coagulant is added to the raw water, and a part of SS such as oil, surfactant, mud and the like is coagulated and settled to reduce the load in the next membrane separation unit 3, and the pump, Prevents clogging of valves and connecting pipes.

  As shown in the figure, the coagulation sedimentation processing unit 2 is separated into three tanks of a first tank 24, a second tank 25, and a third tank 26 by a first partition wall 27 and a second partition wall 28. For this reason, the planar area of the coagulation sedimentation processing unit 2 is the total of the first tank 24, the second tank 25, and the third tank 26.

  A required amount of flocculant is added into the first tank 24 by the flocculant supply machine 22. At this time, when the flocculant is liquid, the metering pump is operated, and when the flocculant is powdery, the metering feeder (not shown) is operated and added, but the operation method and operation method are simple, Since maintenance is easy, it is preferable to use a powdery flocculant. When using a powdery flocculant, it is preferable to use a fixed screw feeder that can prevent powder blocking and easily adjust the supply amount. Further, an agitation paddle, screw agitator, etc. It is more preferable to use a quantitative screw feeder equipped with a bridging prevention mechanism.

  Further, as the flocculant, a flocculant having a sedimentation rate of preferably 0.3 to 3.0 cm / min, more preferably 0.5 to 2.0 cm / min is used. When the sedimentation rate is within the above range, sedimentation separability is good, so that the volume of the sedimentation tank can be reduced (the planar area of the coagulation sedimentation treatment unit 2 can be reduced) and the quality of the treated water can be improved.

  The sedimentation speed is defined as the time T required for 90% of the flocs flocs existing immediately after stirring into a 1 liter beaker containing 1 liter of drainage to settle Lcm from the water surface and deposit on the bottom. And calculated by L / T. Specifically, the turbidity of the supernatant is examined immediately after stirring and at each sedimentation time, and the time and sedimentation distance when the turbidity is reduced by 90% are measured and calculated.

  After the flocculant is added in this way, the coagulation sedimentation process is performed, and the supernatant liquid overflowing from the first tank 24 over the first partition wall 27 is caused to flow into the second tank 25, and similarly, the second partition wall 28. The supernatant liquid overflowing beyond is allowed to flow into the third tank 26. Reference numeral 21 denotes a stirrer for stirring the inside of the first tank 24. The sediment accumulated in each tank of the coagulation sedimentation processing unit 2 is appropriately extracted from the bottom by operating each on-off valve.

  The flocculant is prepared by precipitating a highly stabilized low-concentration oil component to reduce the load on the membrane separation part, and one or more selected from organic flocculants and an ionic mineral that adsorbs and separates the oil component. It is preferable to combine one or more inorganic flocculants included as essential components. As these organic and inorganic flocculants, known ones can be used, but the above-mentioned flocculants for car wash wastewater treatment are more preferable. Particularly, the organic flocculants include sodium alginate and polymer cationic flocculants, and are inorganic. Those containing montmorillonite and aluminum sulfate as the aggregating agent are preferred.

  The combination of the organic flocculant and the inorganic flocculant and the order of addition are appropriately selected and determined experimentally depending on the liquid to be treated. An aqueous flocculant (aqueous solution or aqueous dispersion) containing sodium alginate as the organic flocculant is used. When adding, it is preferable to add separately from an aqueous polyvalent metal ion inorganic flocculant.

  The flocculant used in the present invention is a combination of an organic flocculant containing an alginate and / or a cationic polymer flocculant and an inorganic flocculant containing an ionic mineral and / or aluminum sulfate. It is preferable to contain an alginate and a cationic polymer flocculant and include an ionic mineral and aluminum sulfate as inorganic flocculants.

  The content ratio of the organic flocculant and the inorganic flocculant is 2 to 20% by mass, preferably 4 to 14% by mass, more preferably 5 to 13% by mass, and 98 to 20% by mass of the inorganic flocculant. , Preferably it is 96-86 mass%, More preferably, it is 95-87 mass%.

  By using a combination of organic flocculant and inorganic flocculant in such a range, the effect of flocculation treatment can be remarkably enhanced, so that no special adjustment of the addition amount is required, and membrane separation treatment is performed after flocculation treatment. Therefore, the load is reduced and the solid-liquid separation as designed also contributes to the necessity of special adjustment of the addition amount of the flocculant.

  The alginate used as the organic flocculant is preferably sodium alginate, and the cationic polymer flocculants are polyamines, polydicyandiamides, cationized starch, cationic poly (meth) acrylamide, water-soluble aniline resin, polythiourea, polyethyleneimine , Quaternary ammonium salts, polyvinyl pyridines, chitosan and the like. Among these, cationized starch, cationic poly (meth) acrylamide or a mixture thereof is preferable.

  When an alginate and a cationic polymer flocculant are included as an organic flocculant, the content ratio (mass ratio shown by alginate / cationic polymer flocculant) is preferably 1: 2 to 4: 1. 1: 1.5 to 10: 3 is more preferable.

  Examples of ionic minerals used as inorganic flocculants include bentonite, kaolin, montmorillonite and other clay minerals and zeolites. Among these, they are inexpensive, have a large adsorption area, and adsorb emulsion oil. Since it is easy, montmorillonite and bentonite are preferable.

  When an ionic mineral and aluminum sulfate are included as the inorganic flocculant, the content ratio (mass ratio represented by ionic mineral / aluminum sulfate) is preferably 1: 2 to 2: 1, and 1: 1.5. More preferably, it is ˜1.5: 1.

  As organic flocculants, in addition to the above, acrylic copolymers obtained by copolymerizing hydrophilic monomers such as (meth) acrylic acid and (meth) acrylamide, sodium salts of carboxymethyl cellulose, maleic acid copolymers , Surfactants such as poly (meth) acrylamide, sodium lignin sulfonate, soluble starch, polyoxyethylene dipropylamine, polyoxyethylene lauryl ether, polyoxyethylene octylphenyl ether, and (meth) acrylic acid and acrylamide Anionic or nonionic polymer flocculants such as polymers, amphoteric polymer flocculants, low molecular amine flocculants such as propylene diamine, and the like can be included.

  In addition to the above, the inorganic flocculant should contain polyaluminum chloride, magnesium chloride, ferric chloride, ferrous sulfate, ferric sulfate, slaked lime, sodium silicate, sodium aluminate, aluminum alum, etc. Can do.

  As the flocculant of the present invention, when using a combination of organic and inorganic flocculants of sodium alginate, a cationic polymer flocculant and montmorillonite, aluminum sulfate, each component is as follows in the water treatment process: As a result, the water treatment capacity is improved.

  Montmorillonite alone exhibits alkalinity and acts to lower the solution clay by adsorbing oil emulsified with a surfactant. Sodium alginate performs microencapsulation of montmorillonite that has adsorbed oil and contributes to the formation and enlargement of the floc. Since aluminum sulfate exhibits acidity alone, it acts to promote the generation of flocs by charge neutralization of alkaline montmorillonite. The cationic polymer flocculant promotes enlarging by the effect of flock connection, and at the same time performs dehydration of floc.

  Next, the treated water in the third tank 26 of the coagulation sedimentation processing unit 2 is sent to the membrane separation unit 3 for solid-liquid separation. The planar area in the membrane separation unit 3 is the planar area of the separation membrane.

  The filtration process in the membrane separation unit 3 is performed at a low pressure and a constant transmembrane pressure. The filtration method in the membrane separation unit 3 can employ any of an external pressure type cross flow filtration method, an external pressure type dead end filtration method, an internal pressure type cross flow filtration method, and an internal pressure type dead end filtration method. In consideration of detergency for recovery of filtration performance, the cross flow filtration method is good, and the internal pressure type cross flow filtration method is the best.

  On the other hand, the internal pressure type dead end filtration system has an advantage that the apparatus cost can be reduced in addition to the advantage that it can be operated with low power compared to the cross flow filtration system. Furthermore, by making the transmembrane differential pressure constant, there is an advantage that fouling of the membrane can be suppressed compared to a constant flow rate (flux) operation in which the transmembrane differential pressure varies.

  In order to make the transmembrane pressure constant, in addition to the method of controlling the rotation speed of the pump by pressure detection, a valve installed in front of the module inlet or a method of adjusting the circulation pump flow rate may be used. The transmembrane pressure difference is selected from a low pressure range of 5-30 kPa, preferably 5-25 kPa.

  By reducing the transmembrane pressure difference, it is possible to reduce the power and to prevent a decrease in filtration efficiency due to a loss of membrane pressure loss. In addition, since fouling of the membrane is suppressed, the amount of treated water can be maintained stably over a long period of time. By filtering at such a low pressure, the average membrane surface linear velocity at the inlet and outlet of the membrane in the internal pressure type cross flow filtration method can be reduced, preferably 0.1 m / second or less, more preferably 0.08 m / second. It operates at the following average film surface linear velocity.

The membrane used in the membrane separation unit 3 preferably has a pure water permeation rate of 300 to 3,000 LMHK, more preferably 500 to 2500 LMHK. When the pure water permeation rate is within the above range, the membrane separation property is good, so that the volume of the membrane treatment unit 3 can be reduced (the plane area of the membrane treatment unit 3 can be reduced) and the quality of the treated water is also improved. it can. The pure water permeation rate is the amount of permeated water when pure water permeates through a 1 m ² membrane for 1 hour at 100 kPa.

  The membrane used in the membrane separation unit 3 is preferably a hollow fiber membrane selected from cellulose acetate-based, polysulfone-based, and polyacrylonitrile-based ultrafiltration membranes. From the viewpoint of fouling resistance, cellulose acetate-based ultrafiltration is preferable. A membrane is more preferred. Further, this membrane preferably has a molecular weight cut-off of 10,000 to 500,000, more preferably 100,000 to 300,000.

  Next, the treated water treated by the membrane separation unit 3 is sent to the activated carbon treatment unit 4 and subjected to activated carbon treatment to adsorb and remove odor components mainly due to oil and the like and the remaining surfactant. The planar area of the activated carbon treatment unit 4 is the planar area of the activated carbon filled in the container.

  The contact method of the activated carbon and the treated water in the activated carbon treatment unit 4 is not limited, and for example, a method of passing the treated water through an activated carbon filter can be applied.

  In the car wash wastewater treatment apparatus of the present invention, by combining the coagulation sedimentation treatment unit 2, the membrane separation unit 3 and the activated carbon treatment unit, the removal rate of oil, surfactant, SS, etc. can be increased synergistically, There is no need to adjust the amount of the flocculant added according to the change in the drainage composition.

  Next, the treated water treated by the activated carbon treatment unit 4 is sent to the water storage unit 5 to be stored. The water sent to the water storage section 5 can be reused again as washing water for a car wash or the like. By providing the water storage unit 5 in this way, it becomes easy to reuse treated water.

  As shown in the figure, a back pressure washing tank 6 can be provided between the membrane separation unit 3 and the activated carbon treatment unit 4. The back pressure washing tank 6 stores the treated water that has been subjected to the solid-liquid separation treatment in the membrane separation unit 3 and is used as the back pressure washing water.

  In the car wash wastewater treatment apparatus of the present invention, the wastewater containing oil and surfactant is treated in the order of the coagulation sedimentation treatment unit 2, the membrane separation unit 3, and the activated carbon treatment unit 4, and this treatment was continued. In this case, dirt may adhere to the membrane surface of the membrane separation unit 3 and the solid-liquid separation performance may deteriorate. For this reason, it is desirable to maintain the solid-liquid separation performance in a stable state by performing back pressure washing at appropriate intervals.

  The back pressure cleaning can be applied by a method in which treated water in the water storage unit 5 is press-fitted from the permeate side to the stock solution side of the membrane separation unit 3. The interval of back pressure washing is preferably 15 to 60 minutes, and more preferably 20 to 45 minutes. The flow rate during back pressure washing is preferably 2 to 20 m / day, more preferably 5 to 15 m / day.

  Moreover, in the case of back pressure cleaning, in order to enhance the cleaning effect, a chemical solution such as a sodium hypochlorite aqueous solution from the chemical solution tank 30 can be added to the cleaning water by operating the pump to perform chemical cleaning. When using sodium hypochlorite, the amount of chemical solution added is preferably such that the residual chlorine concentration after backwashing is in the range of 1 to 100 mg / L.

  The car wash wastewater treatment device of the present invention is set so that the treatment amount can be automatically controlled according to the inflow amount of the wastewater, or in order to perform a smooth car wash operation, It can also set so that the treated water of the part 5 can be automatically supplied.

  Hereinafter, the present invention will be described in more detail with reference to an example of car wash wastewater treatment using the car wash wastewater treatment apparatus shown in FIG. The apparatus of the present invention includes the coagulation sedimentation processing unit 2, the membrane processing unit 3, the activated carbon processing unit 4, the water storage unit 5, the membrane treated water storage unit 6, the chemical liquid tank 30, and the normal operation thereof. The auxiliary equipment (flocculating agent supply machine 22, pump, etc.) and the pipes connecting these.

Example 1
As the car wash wastewater treatment apparatus, the one shown in Table 1 was used. As the coagulant used in the coagulation sedimentation processing unit 2, a mixed coagulant (sedimentation rate 1 cm / min) composed of montmorillonite, aluminum sulfate, sodium alginate, and cationic polyacrylamide (mass ratio 48/48/2/2) is used. It added so that it might be set to 50-100 mg / liter with respect to car wash waste_water | drain. The activated carbon treatment part was performed by attaching a column (diameter 15 cm × length 30 cm) packed with 1 kg of coconut shell activated carbon (CW130A, manufactured by Futura Chemical Co., Ltd.) to the membrane permeate line.

  The drainage of the final tank of the oil / water separation tank (having four tanks of the same structure as 20 in FIG. 1) that collects the car wash drainage at the gas station is the raw water (COD 98 mg / liter), and the filtration is an internal pressure crossflow filtration system. (Transmembrane pressure difference 20 kPa). During the filtration operation, the treated water of the water storage unit 5 was used, and the membrane of the membrane treatment unit 3 was subjected to back pressure washing for 1 minute at a rate of once every 30 minutes of filtration time. Back pressure washing was performed at 3.2 m / day for 1 minute.

  The COD was obtained by measuring the COD of the permeate 24 hours after the start of operation with a water quality analyzer manufactured by HACH, and obtaining the COD removal rate. The processing speed was the value of the permeate flowmeter (F1 in FIG. 1) installed in the membrane separation unit 24 24 hours after the start of operation. The results are shown in Table 1.

Examples 2 to 4, Reference Example 1
Using the apparatus shown in Table 1, the operation was performed in the same manner as in Example 1. However, in Reference Example 1 , an oil shut (made by Mitsui Mining Engineering Co., Ltd.) with a sedimentation speed of 0.4 cm / min was used. In Example 4 , a polyethersulfone ultrafiltration hollow fiber membrane was used instead of the cellulose acetate membrane. The results are shown in Table 1.

Comparative Examples 1 and 2
Using the apparatus shown in Table 1, the operation was performed in the same manner as in Example 1. However, cationic polyacrylamide (C4867 manufactured by Mitsui Siac Co., Ltd.) was used with a sedimentation rate of 0.1 cm / min. The results are shown in Table 1.

The conceptual diagram of the waste water treatment equipment of this invention.

Explanation of symbols

2 Coagulation sedimentation section 3 Activated carbon treatment section 4 Membrane separation section 5 Water storage section

Claims (3)

It is a car wash wastewater treatment device having at least a coagulation sedimentation treatment section using a flocculant, a membrane treatment section and an activated carbon treatment section,
The planar area of the entire apparatus is 1 to 5 m ² , the maximum height is 1.5 to 2.5 m, and the ratio of the planar area of each part to the planar area of the entire apparatus is 25 to 55% for the coagulation sedimentation processing part, the membrane processing part Is 2-10%, activated carbon treatment part is 1-10%,
Using a flocculant having a sedimentation rate of 0.5 to 3.0 cm / min in the coagulation sedimentation processing section,
A car wash wastewater treatment device installed in a car wash garment where the COD removal rate calculated from the following formula is 30% or more.
COD removal rate (%) = (COD of car wash wastewater-COD of treated water) / COD of car wash wastewater x 100 It is a car wash wastewater treatment device having at least a coagulation sedimentation treatment section using a flocculant, a membrane treatment section and an activated carbon treatment section,
The planar area of the entire apparatus is 1 to 5 m ² , the maximum height is 1.5 to 2.5 m, and the ratio of the planar area of each part to the planar area of the entire apparatus is 25 to 55% for the coagulation sedimentation processing part, the membrane processing part Is 2-10%, activated carbon treatment part is 1-10%,
Using a flocculant having a sedimentation rate of 0.5 to 3.0 cm / min in the coagulation sedimentation processing section,
A car wash wastewater treatment apparatus installed at a car wash station of a vehicle having a treatment speed per unit volume calculated from the following formula of 0.25 to 0.65 (1 / hr).
Processing speed per unit volume (1 / hr) = Processing speed (m ³ / hr) / Device volume (m ³ ) The car wash wastewater treatment apparatus according to claim 1 or 2 , wherein a pure water permeation rate of the separation membrane in the membrane treatment unit is 300 to 3,000 LMHK.

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