KR100404052B1 - Recoating Filtering System - Google Patents

Abstract

The present invention relates to a coating filtration system, and more specifically, a storage tank of the contaminated tank and the treatment tank; Treated water pump; Precoat tanks; A precoat filter comprising an air cylinder and a filter housing in which a plurality of mono tube filters are embedded; Sludge tank; And a feed pump, so that the sludge and the filtration aid of the filter surface are shaken off when the precoating operation, the filtration operation, and the filtration pressure reaches a predetermined pressure, and the sludge and the filtration aid are attached to the filter surface in a uniform mixing state. And the coating circulating operation to coat, and when the sludge reaches the saturation in accordance with the repeating of the recording circulating operation, shake off the sludge and transfer the liquid and the sludge to the sludge tank by compressed air, in the sludge tank, the dehydration liquid to the treated water tank The remaining dry cake is discharged and discharged to the outside, so that the sludge is repeatedly performed to prevent sludge from penetrating into the filtration surface and to block the pores. It is easily detached and can be used without changing the filtration membrane, and at the same time maximizes the filtration capacity. The first has an effect that can be reused to minimize the waste of resources, waste generation, treatment costs by several times to several tens of meeting Lee coating.

Description

Recording Filtering System

The present invention relates to a coating filtration system, and more particularly, by attaching a filtration aid to the surface of the filtration membrane to prevent sludge, such as solid particles, from penetrating the filtration surface to block the pores, thereby protecting the filtration membrane, and the mono tube as a filter. Easily detached during backwashing to enable use without replacement of the filtration membrane, maximizing filtration capacity with the largest filtration area in a small container, and several times by coating filtration aid such as diatomaceous earth once used It can be reused or dozens of times, preventing the waste of resources is fundamental, and relates to a filtering filtration system that can improve the economics by minimizing the amount of waste generated and waste disposal costs.

In general, in the membrane separation filtration method using a cartridge filter or other filtration membrane, as the amount of sludge accumulated on the surface of the filtration membrane increases, the filtration pressure rapidly increases, and the flow rate of the filtration is rapidly reduced. Before the sludge accumulated in the filtration membrane does not pass the required flow rate, there is a problem that the cartridge or the filtration membrane must be replaced or restored to a clean state through an operation such as washing.

Particularly, in the sludge-rich liquid such as machining fluid, the particles of about 0.1μ to 0.3μ are rapidly increased in filtration pressure and the filtration flow rate is drastically reduced even if only a small amount of accumulation is made. Excessive work such as replacement or washing of the very large loss occurs because it was practically impossible to use.

As a filtration method to solve the above problems, there was a precoating filter method for precoating a filtration aid. The above-described method is a method of applying a predetermined amount of a filter aid to the surface of a cloth, a mesh, a porous ceramic core, a cartridge, a filter membrane, and the like to prevent direct contact between the substances to be filtered and then filtering. That is, it is a filtration system that maximizes the filtration area by the characteristics of the filter aid applied to the surface, and efficiently collects the fine particles of 0.3μ to 3.0μ to keep the filtrate at all times clean.

However, the precoating filtration method as described above also leads to problems as exemplified below by simple precoating. It is permanently listed below.

In general, high quality filter aids should be pure, inert, have many long thin channels, have high permeability, and have a stable structure to withstand pressure. Viii), cellulose, activated carbon, silica and the like are used. In particular, diatomaceous earth can be removed efficiently and economically from extremely fine things such as bacteria to suspended matter on colloids due to its very high porosity (specific surface area) and absorption ability. It is widely used for the filtration of processes requiring purity.

Thus, as an example of using diatomaceous earth as a filtration aid, a dust collecting device equipped with a filter coated with diatomaceous earth has been filed as Utility Model Application No. 2000-20058.

However, the above application has the disadvantage that the valuable resources are wasted by disposing of the diatomaceous earth after reusing it without reuse of the diatomaceous earth, thereby increasing secondary disposal costs and increasing environmental pollution. In order to operate a plurality of dust collectors in parallel, they must be connected in parallel to each other and operate in conjunction with each other. Therefore, problems such as increase of the equipment cost and complexity of operation (particularly, complexity of dust removal operation to shake off the filter bag) are one of the disadvantages. There was this. Furthermore, it is difficult to apply to materials such as liquids other than dust or odorous substances in the air, and there is a general disadvantage that the operation of the entire apparatus should be stopped when one device fails for continuous operation.

The present invention has been invented to solve the above problems, the object of the present invention is to attach a filter aid on the surface of the filter membrane to prevent the sludge, such as solid particles to penetrate the filter surface to block the pores and to protect the filter membrane Using a mono tube as a filter, it is easily detached during backwashing, so that it can be used without exchanging the filtration membrane, and the filtration capacity is maximized with the maximum filtration area in a small container. It can be reused several times or dozens of times by coating to prevent the waste of resources, and to provide a filtering filtration system that can improve the economics by minimizing the amount of waste generated and waste disposal costs.

In order to achieve the above object, the present invention is a filtration system for releasing the sludge to the outside by pre-coating with a filter aid,

A storage tank (1) in which a contaminated water tank (11) storing contaminated water to be filtered by the filtering aid and a treated water tank (12) storing filtered water are stored; A treated water pump (2) for discharging the treated water to the outside when the treated water exceeds a predetermined boundary level of the treated water tank (12); A precoat tank (3) for introducing and discharging the filtration aid; Filtration aid flowing from the precoat tank 3 and contaminated water from the contaminated water tank 11 are introduced and a plurality of mono tube filters 411 are built-in to carry the filtered filtration. A precoat filter 4 including a filter housing 41 to which an auxiliary agent is attached and an upper air cylinder 42; A sludge tank 5 for introducing and treating the liquid and the sludge which are transferred from the filter housing 41; And comprising a feed pump (feed pump, 6) for the transfer of the contaminated water and the filter aid,

When the precoat filter 4 receives the filtration aid from the precoat tank 3 by the feed pump 6 and becomes full, the precoat filter 4 transfers the filter to the precoat tank 3 to filter the surface of the filter 411. Pre-coating operation to attach and coat auxiliary agents,

After the precoating operation, the filter pump receives the contaminated water from the contaminated water tank 11 by the feed pump 6 and filters the filtered water and transfers the filtered treated water to the treated water tank 12,

When the filtration pressure reaches a certain pressure after the filtration operation, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time to shake off the filtration aid and diatomaceous earth on the surface of the filter 411. In addition, after the sludge and the filter aid are attached and coated on the surface of the filter in a uniform mixed state by the precoating operation, the coating circulation operation is repeated again.

When the sludge attached to the filter 411 reaches a saturation state as the recording circulation operation is repeated, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time. After the sludge on the surface and the filtering aid are shaken off, the liquid and sludge in the filter housing 41 are transferred to the sludge tank 5 by compressed air, and the filter housing ( 41) Backwashing in which the dehydrating liquid dehydrated by the compressed air by flowing the liquid and sludge introduced from the dewatering liquid is discharged to the treatment tank 12 and the remaining dried cake is discharged to the outside. Characterized in that the operation is performed repeatedly.

1 is a view schematically showing the entire system of the present invention,

Figure 2 is a block diagram illustrating the processes performed under the system of the present invention in order.

※ Explanation of main parts of drawing ※

1: storage tank 11: contaminated water tank

12: treated water tank 2: treated water pump

3: Precoat Tank

31: stirrer 32: oil gauge

4: Precoat Filter

41: filter housing 42: air cylinder

43: pressure gauge 411: filter

5: sludge tank 6: feed pump

Hereinafter, with reference to the accompanying drawings will be described in more detail the system according to the present invention.

1 is a schematic diagram of an overall system of the present invention, and FIG. 2 is a block diagram sequentially illustrating a process performed under the system of the present invention.

As shown, the system of the present invention is a filtration system that is generally precoated with a filtration aid and then filtered to discharge sludge to the outside, where a contaminated water tank 11 in which contaminated water is stored and a treated water tank in which treated water are stored. A reservoir 1 in which 12 is divided; Treated water pump 2; Precoat Tank (3); Precoat filter including filter housing 41 into which filter aid and contaminated water are introduced, and filters 411 of a plurality of mono tubes are incorporated, and an upper air cylinder 42. Filter, 4); Sludge tank 5; And comprising a feed pump (feed pump, 6),

When the precoat filter 4 receives the filtration aid from the precoat tank 3 by the feed pump 6 and becomes full, the precoat filter 4 transfers the filter to the precoat tank 3 to filter the surface of the filter 411. Pre-coating operation to attach and coat auxiliary agents,

After the precoating operation, the filter pump receives the contaminated water from the contaminated water tank 11 by the feed pump 6 and filters the filtered water and transfers the filtered treated water to the treated water tank 12,

When the filtration pressure reaches a certain pressure after the filtration operation, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time to shake off the filtration aid and diatomaceous earth on the surface of the filter 411. In addition, after the sludge and the filter aid are attached and coated on the surface of the filter in a uniform mixed state by the precoating operation, the coating circulation operation is repeated again.

When the sludge attached to the filter 411 reaches a saturation state as the recording circulation operation is repeated, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time. After the sludge on the surface and the filtering aid are shaken off, the liquid and sludge in the filter housing 41 are transferred to the sludge tank 5 by compressed air, and the filter housing ( 41) Backwashing in which the dehydrating liquid dehydrated by the compressed air by flowing the liquid and sludge introduced from the dewatering liquid is discharged to the treatment tank 12 and the remaining dried cake is discharged to the outside. It is made to repeat the operation.

Hereinafter, each of the above apparatuses will be described in detail and in detail, the circulation filtration by the coating of the filtration aid will be described in order.

The storage tank 1 is divided into a contaminated water tank 11 in which contaminated water to be filtered by the filtering aid is stored, and a treated water tank 12 in which filtered water is stored. In addition, the dewatered liquid dewatered from the sludge tank 5 is introduced into the contaminated water tank 12 of the storage tank 1 to greatly reduce the burden of environmental pollution and treatment costs due to the back washing operation. It is supposed to be.

As the filter aid used in the present invention, one or more selected from the group consisting of diatomaceous earth, cellulose, activated carbon and silica can be used. It is preferable to use diatomaceous earth.

The treated water pump 2 is connected to the reservoir 1 as a pump for discharging the treated water to the outside when the treated water exceeds a predetermined boundary level of the treated water tank 12.

The precoat tank (3) is a tank for precoating the filter 411 with the filter aid before the filtration operation by inflow and outflow of the filter aid, to maintain a proper flow rate at all times. It is equipped with a level control system and a stirrer and an oil level gauge are provided to promote the mixing of the filter aid. In addition, the precoat tank 3 should have an appropriate capacity according to the characteristics of the filtrate and the filtration area, and smooth the flow of the liquid.

The precoat filter (4) is a filter of a plurality of mono-tubes by introducing a filter aid to be transferred from the precoat tank (3) and the contaminated water from the contaminated water tank (11) in a vertical type 411 includes a filter housing 41, the upper air cylinder (42) is attached to the filter housing 41 is attached to the transport aid.

That is, a bumping air cylinder 42 is installed on the upper side to generate an impact in the vertical operation before the back washing operation, thereby desorbing foreign substances attached to the filter surface of the mono tube. The lower part has a structure that can prevent sludge settling as much as possible, and has a structure that keeps the flow of the filtrate in an ideal state.

In addition, a mono tube filter 411 of a quantity corresponding to the required filtration area is lifted by the air cylinder 42, and the packing or seal is made of a special material to have a sufficient lifespan. The sealed state is maintained so that sludge does not pass through the filtration membrane and does not escape.

Furthermore, a sight glass and a pressure gauge are installed to visually check the filtration state, and an inlet, an outlet, an air vent, and a flushing air nozzle are installed. The material is made of SS41, SUS304, SUS316, etc. It can also be manufactured in special specifications such as rubber lining.

On the other hand, the filter 411 of the mono tube (mono tube) is preferably made of a polypropylene (polypropylene mono tube) as a plastic material. This is to maximize the filtration capacity by having a maximum filtration area in a small container.

The sludge tank 5 is introduced into the liquid and sludge conveyed from the filter housing 41 and dehydrated by compressed air by dewatering the dewatered liquid to the treatment tank 12 and the remaining dried cake (Cake) Is a device for processing the back washing operation by emitting to the outside.

That is, in the sludge tank 5 of the present invention, since the generated backwashing liquid is filtered by the filter aid once again at the pressure of air rather than the filter, the dehydration liquid is sent to the contaminated water tank 11 in a clean state. By repeating the filtration system of the present invention to maximize the filtration efficiency, while dehydrating sufficiently at a predetermined air pressure to make a cake of about 70% dried state, simply desorption by a switch operation By discharging the cake to the outside to solve the problems of environmental pollution and treatment costs due to the backwashing liquid in the conventional general filtration device, and the treatment is very difficult, further conventional separate dehydration device is required I do not want to.

In addition, it is convenient to check the recovery state of the liquid from the outside, it is possible to prevent the leakage of the liquid by malfunction.

The feed pump 6 is a device for transporting contaminated water and filtration aids.

The above configurations are basically necessary for the filtration system of the present invention. Preferably, in addition to the above-described devices, a flow control valve, a pressure transmitter, and the like are added to be very efficient. In addition, preferably, an operating panel is added in addition to the manual operation so that the pre-coating operation, the filtration operation, the recording circulation operation, the back washing operation, etc. are fully automated to exhibit each function as effectively as possible. good.

Hereinafter, the operation by the apparatuses of the present invention described above will be described in detail. However, the system of the present invention is a system in which the following operations are repeatedly performed.

1) precoating

When the precoat filter 4 receives the filtration aid from the precoat tank 3 by the feed pump 6 and becomes full, the precoat filter 4 transfers the filter to the precoat tank 3 again. A filter aid is attached and coated on the surface.

2) Filtration operation

After the precoating operation, the contaminated water is supplied from the contaminated water tank 11 by the feed pump 6 and filtered. The treated water discharged after the filtration is transferred to the treated water tank 12.

3) Recording circulation operation

After the filtration operation, when the filtration pressure reaches a certain pressure, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time to shake off the sludge on the surface of the filter 411 and the filtration aid. In addition, the sludge and the filter aid are attached and coated on the surface of the filter in a uniform mixed state by the precoating operation, and the filtration operation is repeated again.

4) Back washing operation

When the sludge attached to the filter 411 reaches a saturation state as the recording circulation operation is repeated, the feed pump 6 is stopped and bumped by the air cylinder 42 for a predetermined time. After the sludge on the surface and the filtering aid are shaken off, the liquid and sludge in the filter housing 41 are transferred to the sludge tank 5 by compressed air, and the filter housing ( 41) and the dewatered and dehydrated liquid is dehydrated by compressed air after flowing from the sludge and the sludge is discharged to the treatment tank 12 and the remaining dried cake is discharged to the outside.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples should not be construed as limiting the scope of the present invention, and ordinary changes may be made by those skilled in the art within the scope of the present invention.

Examples 1-5

The following table is an example showing an application example of the PCF (PRECOATING FILTER) TYPE system. (Recoat happens once every 3 hours)

Application Case of PCF TYPE System (Yoosung Corporation) CLIENT Yusung Corporation PROCESS RING GRINDING FLUID NAME Water soluble oil Processing capacity 60 T / H SS before treatment 36 PPM SS after treatment 1.2 PPM SLUDGE type Iron and Carbon SLUDGE occurrence 50 KG / DAY Diatomaceous earth consumption (once) 20 KG Monthly Diatomite Usage 200 KG

As can be seen in Table 1, it took three days until the filtration pressure of diatomaceous earth in Example 1 reached 2.5 kgf, and used diatomaceous earth for one month by replacing diatomaceous earth once every three days. The effective filtration area was 25 m 2.

Application Case of PCF TYPE System (Yoosung Corporation) CLIENT Yusung Corporation PROCESS RING GRINDING FLUID NAME Water soluble oil Processing capacity 36 T / H SS before treatment 17 PPM SS after treatment 0.8 PPM SLUDGE type Iron and Carbon SLUDGE occurrence 15 KG / DAY Diatomaceous earth consumption (once) 10 KG Monthly Diatomite Usage 40 KG

As can be seen in Table 2, it took 7.5 days until the filtration pressure of diatomaceous earth in Example 2 reached 2.5 kgf, and used diatomaceous earth for 40 months to replace diatomaceous earth once every 7.5 days. The effective filtration area was 15 m 2.

Application Case of PCF TYPE System (Dorco) CLIENT Toruko PROCESS RAZOR GRINDER FLUID NAME Water-insoluble oil Processing capacity 24 T / H SS before treatment 24 PPM SS after treatment 1.0 PPM SLUDGE type SUS, low stone powder SLUDGE occurrence 14 KG / DAY Diatomaceous earth consumption (once) 10 KG Monthly Diatomite Usage 40 KG

As can be seen in Table 3, it took 7.5 days until the filtration pressure by diatomaceous earth in Example 3 was 2.5 kgf, and 40 kg of diatomaceous earth was used for one month by replacing diatomaceous earth once every 7.5 days. The effective filtration area was 15 m 2.

Application Case of PCF TYPE System (FAG Hanwha Bearing) CLIENT FAG Hanwha Bearing PROCESS SUPER FINISHING FLUID NAME Water-insoluble oil Processing capacity 42 T / H SS before treatment 48 PPM SS after treatment 0.9 PPM SLUDGE type STEEL, low stone powder SLUDGE occurrence 48 KG / DAY Diatomaceous earth consumption (once) 20 KG Monthly Diatomite Usage 200 KG

As can be seen in Table 4, it took three days until the filtration pressure by diatomaceous earth in Example 4 reached 2.5 kgf, and used diatomaceous earth for 200 days to replace diatomaceous earth once every three days. , Effective filtration area was 18㎡.

Application Case of PCF TYPE System (Kyung In Yang) CLIENT Kyungin Yang PROCESS Dye Wastewater Treatment Process FLUID NAME Dye wastewater Processing capacity 12 T / H SS before treatment 180 PPM SS after treatment 2.0 PPM SLUDGE type dyes SLUDGE occurrence 50 KG / DAY Diatomaceous earth consumption (once) 8 KG Monthly Diatomite Usage 240 KG

As can be seen in Table 5, it took one day until the filtration pressure of diatomaceous earth in Example 5 was 2.5 kgf, and 240 kg of diatomaceous earth was used for one month by replacing diatomaceous earth once per day. The effective filtration area was 10 m 2.

As a result, the diatomaceous earth replacement period is shorter when the suspended solids concentration (SS) is high (Example 5), and when the suspended solids concentration (SS) is low (Examples 2 and 3), the diatomaceous earth replacement is performed. It can be seen that the period becomes longer.

Comparing the system of the present invention according to the above-described embodiment with a conventional precoat filter system is shown in Table 6 below.

Comparison table with conventional precoat system division PCF 350 DD PCF 350 SD Plain precoat filter Filtration method RECOAT FILTER RECOAT FILTER ONLY PRE-COAT Filtration precision 0.3-1.0μ 0.3-1.0μ 0.3-1.0μ FILTER ELEMENT 80-170 KG / month 80-170 KG / month 240-480 KG / month FILTER HOUSING Diameter (Based on filtration area 40㎡) φ14 PP MONO TUBE φ14 PP MONO TUBE SUS MESH or NYLONE Backwash BUMPING & BACK WASH AIR BUMPING & BACK WASH AIR Back wash air or backwash Sludge Treatment Method DIRECT DRY DRY from SLUDGE RECEIVER Separate dehydration device required (or discharge) Clogging phenomenon (maintenance and maintenance) none none Requires 1-2 times a year FLOW CONTROL INVERTER CONTROL SUPPLY VALVE CONTROL none pros and cons Diatomite Amount 48,000-102,000 won / month 48,000-102,000 won / month 144,000-288,000 won / month Equipment cost (depreciation basis, unit thousand won) medium versus versus Installation area small medium versus Filtration precision Great Great usually BACK WASH degree Great Great Bad Intermittent driving possible Impossible Impossible Filtration and Dewatering No simultaneous progress Simultaneous progress is possible No simultaneous progress Tank cleaning and cleaning solution expenses (based on 100,000 won per person, 2,500 won per wash) No need for tank cleaning, once a year No need for tank cleaning, once a year Tank cleaning two people two times 400,000 won / year, washing amount exchanged twice 1,000,000 won / year

As described above, the present invention attaches a filtration aid (preferably diatomaceous earth) to the surface of the filtration membrane to prevent sludge, such as solid particles, from penetrating the filtration surface to block the pores, thereby protecting the filtration membrane, and preferably a mono tube (preferably Polypropylene mono tube) is used as a filter to easily detach when backwashing, so that it can be used without exchanging the filtration membrane, and to maximize the filtration capacity with the largest filtration area in a small container. By reusing the filter aid several times or tens of times by coating, prevention of waste of resources is basic and has the effect of improving economic efficiency by minimizing the amount of waste generated and waste disposal costs.

In addition, the maintenance structure is convenient and convenient with a simple and efficient structure, and it is possible to ensure constant and uniform filtration performance at all times, and the liquid discharged during backwashing is dehydrated and treated, and only the sludge in the dried cake state is discharged. Therefore, the treatment is very easy to prevent pollution of the surrounding environment and has the effect of not needing a separate dehydration device.

Furthermore, the use of a mono tube (preferably polypropylene mono tube) as a filter allows maximum filtration area in a small container, thereby maximizing filtration capacity.

Specifically, the effects are as follows.

1) High Precision Filtration

The precoating technology of the complete filter aid filters out sub-micron microparticles that are not possible with conventional filters.

2) semi-permanent life

Mono tube (preferably polypropylene mono tube) is a special structure that prevents clogging and has a strength comparable to that of ordinary filter cloths.It is almost permanently used because it does not cause clogging like SUS mesh. And the problems caused by this can be completely prevented.

3) large capacity processing

The filter made of mono tube has the largest filtration area in the same size container, so the processing capacity is much higher than that of general filter.

4) Best Economics

The application of the filtering aid (preferably diatomaceous earth) is reused several times to several times to minimize the use of the filter aid, so it has superior economical efficiency compared to the conventional filter and minimizes the generation of waste. This also reduces the processing cost.

5) Fully automatic operation

Anyone can operate easily with fully automatic operation in which all processes from pre-coating to filtration and sludge treatment are batch processed.

6) Compact Design

Due to the efficient structure and system of the installation, the installation area is extremely small, and a variety of products from the small to the portable type can be standardized, and also the complete confidentiality is prevented from evaporating or spilling the filtrate to contaminate the surrounding environment. Keep it.

Looking at the application with the above effects in detail as follows.

Iii. Water and wastewater related industries: Various wastewater recycling filtration devices such as suspended solids and oil phase oil removal in circulating water such as cooling water and boiler water, effluent suspended solids and color filtration device, brewing liquor filtration device, food processing liquid filtration device, Filtration device for removal of suspended solids from all other industrial wastewaters, such as aquatic product processing liquid filter, livestock wastewater aftertreatment filter device, mine wastewater

Ii. Surface treatment industry: Zinc plating liquid filtration device, nickel plating liquid filtration device, clarified copper plating liquid filtration device, barrel polishing waste water recycling filtration, degreasing solution filtration device, pretreatment liquid filtering device

Iii. Machining Industry: Suspended solids in water-soluble oils such as grinding oil, lubricating oil, hydraulic oil, and co-sharing, filtration device for removing oil phase oil, discharge processing liquid filtration device, filtration device for waste oil purification, filtration device for ultrasonic soluble liquid, Filtration device for suspension solid solution separation, PCB printed circuit board polishing liquid filtration

Iii. Food and medicine industry

Removal of suspended solids and dissolved organic matter in the preparation of drinking water, purification of fermentation broth, concentration and purification of protein, preparation of sterile water for medical use

Iii. Sewage and heavy water treatment

Removal of suspended solids and dissolved organics in sewage, removal of suspended solids and dissolved organics in heavy water

Iii. Etc

Reuse of car wash waste water, heavy water treatment in buildings, swimming pool water purification, household water purification, etc.

Claims (8)

delete delete delete delete delete In the filtration method of pre-coating a filter with a filtration aid to filter the contaminated water to discharge the sludge to the outside, Iii) A monotube filter of plastic material provided in the precoat filter 4 by transferring the filtration aid filled in the precoat tank 3 to the precoat filter 4 using a feed pump 6. 411) attaching and coating a filter aid on the surface of 0.6 to 1.1Kg / m ² with respect to the effective filtration area of the monotube filter 411, Ii) After the step iii) is completed, the contaminated water filled in the contaminated water tank 11 of the storage tank 1 is transferred to the precoat filter 4 using the feed pump 6, and then filtered and filtered. Transferring the treatment tank 12 to the storage tank 1; Iii) When the filtration pressure reaches the predetermined pressure during the operation of step ii), the feed pump 6 is stopped and the bumping air cylinder 42 is operated to provide a monolithic plastic material provided in the precoat filter 4. Desorbing the sludge and the filtration aid adhering to the surface of the tube filter 411, Iii) sequentially repeating steps iii) to iii) until the sludge attached to the plastic monotube filter 411 provided in the precoat filter 4 reaches a saturation state, Iii) after the end of step iv), stop the operation of the feed pump 6 and operate the bumping air cylinder 42 so that the surface of the plastic monotube filter 411 provided in the precoat filter 4 Desorbing the sludge and the filter aid adhering to the sludge and transferring the liquid and the sludge in the filter housing 41 to the sludge tank 5 by compressed air, and Iii) After the step iii) is finished, the liquid and sludge transferred to the sludge tank 5 are dehydrated with compressed air, and the dehydration liquid is recovered to the contaminated water tank 11 of the storage tank 1 to prevent secondary contamination and the rest. The coating method of claim 1, wherein the dried cake is discharged to the outside. The method of claim 6, The filtering aid is a diatomaceous earth, cellulose, activated carbon, silica or a mixture thereof. The method according to any one of claims 6 to 7, And a stirrer (31) and an oil level gauge (32) for promoting a mixture of diatomaceous earth in the precoat tank (3).