KR101887408B1 - Non-point Pollution Source Reducing Device - Google Patents

Abstract

The present invention relates to an apparatus for reducing a non-point pollution source, wherein the apparatus comprises a water collection tank partitioned into: an inlet tank communicating with an inlet in which a non-point contaminated water including pollutants generated from the non-point pollution source is introduced; a processing tank connected to a downstream of the inlet tank to collect the pollutants, and coupled with a discharge hole for discharging treated water and a filtering part for backwashing the collected contaminants; and a backwashing tank connected to the lower side of the processing tank to accommodate the collected pollutants backwashed in the processing tank. The filtering part comprises: a floating medium layer composed of a plurality of floating media to form an air gap in which contaminants received and transferred in the processing tank are able to be collected; a medium lifting restriction member coupled to the processing tank at a predetermined depth from the discharge hole to limit the lifting of the floating media; an opening and closing valve for opening and closing a backwashing water discharge hole which is penetrated to be discharged to the backwashing tank when the collected pollutants are backwashed; and a driving member for providing driving force to the opening and closing valve to be able to move up and down. According to the present invention, it is possible to rapidly and efficiently backwash a collected material collected and filtered among non-point pollutants.

Description

[0002] Non-point Pollution Source Reducing Device [

The present invention relates to a non-point pollution source reduction apparatus, and more particularly, to a non-point pollution source reduction apparatus that improves the structure so that contaminants generated in non-point pollution sources can be removed and backwashed.

Point Pollution Source and Non-Point Pollution Source are classified according to pollution sources that pollute water quality.

first. Point pollution sources occur in specific places, such as industrial wastewater discharged from domestic sewage, factories, etc. discharged from general households or business areas, and livestock wastewater generated from large-scale livestock facilities, and it is easy to collect, As seasonal impacts are relatively small, it is easy to design and maintain the treatment facilities such as pipelines and treatment plants because the annual production can be predicted. Point pollution sources are examples of wastewater discharge facilities such as factories and business sites in the Water Environment Protection Law.

On the other hand, it is difficult to design and maintain treatment facilities because non-point pollution sources are difficult to collect because pollutant outflow and discharge routes are not clearly distinguished, and amount of generated pollutants and emissions are highly dependent on weather conditions such as precipitation. These non-point pollutants include fertilizers and pesticides that are not absorbed by the crops and remain in agricultural land, livestock feces grazed on grassland, untreated livestock wastewater from livestock farming, air pollutants mixed with rainwater, sediments on road roads, And the number of mixed sewage sewage and rainwater flowing into the river exceeding the designed amount during rainfall.

Here, the point pollution source and the non-point pollution source are relative concepts. In the case of a factory, for example, a process facility that collects plant wastewater collected through a conduit and treated through a water pollution prevention facility is a point pollution source, Factory sites such as the yard that discharges inflowing runoff water become nonpoint source.

Therefore, in order to protect the quality of water resources and ensure the integrity of water ecosystems, measures should be taken to manage point pollution sources such as wastewater treatment facilities and sewage treatment facilities, and measures should be taken to reduce nonpoint pollutants from the stage of land development planning , Such a scheme has been proposed.

Such conventional techniques include a method of filtering the initial storm of the road by a filter of upstream or downstream type in a manhole or the like, in particular, a suspension material or a suspended solid material.

The prior art has a problem that it is difficult to appropriately maintain the function for treating various kinds of non-point pollutants by non-motive force.

[Related Technical Literature]

Japanese Patent Application Laid-Open No. 10-1695463 (published on Jan. 16, 2017)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a nonpoint source depletion device capable of quickly and efficiently backwashing captured substances trapped in non-point contaminants.

Another object of the present invention is to provide a non-point source reduction device that is simple and convenient to use.

It is still another object of the present invention to provide a filtration system capable of effectively filtering out and separating the self weight and agglomerated materials of non-point pollutants by filtering up non-point pollutants using a floating filter medium in a bottom- And to provide a non-point pollution source abatement apparatus capable of maintaining the service life of the floating filter medium for a long time.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a nonpoint source depletion reduction apparatus for reducing contaminants generated in a nonpoint source of contamination, the apparatus comprising: an inflow vessel communicated with an inlet through which nonpoint contaminated water containing contaminants generated in the non- A treatment tank in communication with a downstream side of the treatment tank and connected to an outlet for collecting the pollutant and discharging the treated treatment water and a filtration unit capable of backwashing the trapped pollutant, Wherein the filter comprises a plurality of floating filter media layers formed of a plurality of floating filter media so as to form voids capable of collecting the contaminants received and transported in the treatment tank, , The floatation material is restrained from rising to a predetermined depth from the outlet An open / close valve for opening and closing a reverse water discharge port through which the collecting material is discharged so as to be discharged into the reverse osmosis at the time of backwashing, and a driving member for providing a driving force for elevating the opening / closing valve And a non-point pollution source reduction apparatus characterized by comprising:

In addition, the filtration unit may be configured to open and close the on-off valve so that the collecting material and the floating filter material aggregated between the floating filter materials in a process of being backwashed in the processing tank are detachably linked to the opening / closing valve, It is preferable to further include a collecting material separating member.

The collecting material separating member is disposed below the filter re-ascending limit member and moves in conjunction with the opening / closing valve to collectively collect the collecting material between the floating filter material and the floating filter material, And a vibration motor and a vibrator disposed in the material separation network or the floating filter medium layer and capable of providing backwashing vibration to the trapping material between the floating filter media.

In addition, in order to back up the capturing material in the treatment tank, the control device repeatedly controls the lifting and lowering of the opening / closing valve intermittently in accordance with the set time to separate the trapping material and the floating filter material, .

In addition, the floating filter material preferably has a spherical shape and has a specific gravity in the range of 0.02 or more and less than 0.1, and is preferably elastically deformed according to the water pressure.

The compression strength of the floating filter medium is preferably 0.5 kg / cm 2 to 1 kg / cm 2.

The backwash in the treatment tank is preferably performed when the filtration performance in the filtration unit exceeds a set range.

Therefore, according to the present invention, it is possible to provide a non-point pollution source abatement device capable of quickly and efficiently back-up the collected substances trapped in non-point pollutants.

In addition, it is possible to provide a nonpoint source pollution reduction device that is simple and convenient to use.

In addition, in the upflow type flow, the filtration efficiency is improved by filtering the non-point pollutants using the floating filter media and effectively backing up and separating the self weight of the non-point pollutant and the aggregated material by the downflow type flow, It is possible to provide a nonpoint pollution source abatement device capable of maintaining the service life of the filter material for a long time.

1 is a conceptual view for explaining a non-point source and a point source to which a non-point source reduction device according to an embodiment of the present invention is applied;
FIG. 2 is a partially cutaway perspective view of a non-point pollution source reduction apparatus according to an embodiment of the present invention;
3 is an exploded perspective view of the filtration unit of FIG. 2,
FIGS. 4 and 5 are partial cutaway perspective views for explaining the operation of the non-point pollution source reduction device,
FIG. 6A is a conceptual diagram for explaining a change in floating filter media according to the depth set in the processing tank,
FIG. 6B is a conceptual diagram for explaining the volume change of the floating filter media during filtration and backwashing, and the process of collecting or coagulating and separating nonpoint-
FIG. 7 and FIG. 8 are graphs showing the filtration efficiency and the volume change of the filter media according to the variation of the water depth,
FIGS. 9A and 9B are photographs showing a state in which non-point pollutants are collected in a floating filter medium layer in a pilot test, and a change in a floating filter medium layer and a non-point pollutant collected are broken and separated during backwashing.

1 to 9B, a non-point pollution source reduction apparatus 100 (hereinafter referred to as a "pollution source reduction apparatus") capable of stably maintaining filtration efficiency by utilizing a floating filter medium and backwash according to an embodiment of the present invention Specifically, it is as follows.

FIG. 1 is a conceptual view for explaining a non-point pollution source and a point pollution source to which a non-point pollution source reduction device according to an embodiment of the present invention is applied, and FIG. 2 is a partial cut perspective view of a nonpoint pollution source reduction device according to an embodiment of the present invention And FIG. 3 is an exploded perspective view of the filtration unit of FIG. 2. FIGS. 4 and 5 are partial cutaway perspective views illustrating the operation of the nonpoint pollution source reduction apparatus. FIG. 6B is a conceptual view for explaining the volume change of the floating filter medium during filtration and backwashing and the process of collecting or coagulating and separating non-point pollutants. FIGS. 7 and 8 are graphs showing the filtration efficiency 9A and 9B are graphs showing changes in the volume of the filter media during the pilot test and the state of the non-point contaminants collected in the floating filter medium layer and the change in the floating filter medium layer during the back- This photograph shows that the collected nonpoint pollutants are destroyed and separated.

As shown in FIGS. 1 to 3, the pollution source reduction apparatus 100 according to an embodiment of the present invention is a pollution reduction apparatus 100 for reducing pollutants generated in a nonpoint pollution source, An inlet 103 communicating with the inlet 103a through which the contaminated water flows, an outlet 103b communicating with the downstream of the inlet 110 to collect the contaminants and discharging the treated water, A processing vessel 120 communicating with the lower side of the processing vessel 120 to receive the trapping material backwashed in the processing vessel 120, The filtering unit 150 includes a plurality of float filter media 152a to form a void capable of trapping the contaminants that are received in the treatment tank 120 and are transported, A floating filter medium layer 152 made of a metal, (154) coupled to the treatment tank (120) at a predetermined depth from the discharge port (103b) so as to restrain the rising of the gas phase filter medium (152a) Closing valve 157 for opening and closing a reverse water discharge port 127 which is capable of being discharged to the discharge port 130 and a driving member 151 for providing a driving force to the opening and closing valve 157 and the collecting material separating net 155 ).

First, as outlined above, point sources and non-point sources are outlined with reference to FIG.

As shown in Fig. 1, the pollutant source is clearly specified, for example, as a factory, a house, etc. The effluent discharged from the pollutant flows into the wastewater treatment plant through the wastewater pipe, and the pollutants are physically and biochemically And the purified water is discharged to streams, lakes, rivers, and the like.

On the other hand, in the case of rain, in the case of the non-point pollution source such as the road shown in Fig. 1, the rain is changed into non-point polluted water including non-point pollutants including clay, soil, 'L'), and the heavy gravels sink down by their own weight and are discharged to rivers, sewage, rivers, etc. through only high-grade water.

When the present invention is applied, the water collecting tank 103 including a manhole of the prior art is provided with a filtering unit 150 to be described later, so that the treated water after being filtered is discharged to a river, sewage, The pollutants collected in the unit 150 are collected in the reverse tank 130 through backwash and transferred to the wastewater treatment plant connected to the wastewater pipe through the reverse water transfer pump 133 and discharged to the river only after the treated water . Through this process, it is possible to reduce contaminants generated in the non-point source from the prior art.

In the present invention, as an example of a non-point source for the sake of convenience of description, for example, the above-mentioned storm occurred in the road is taken as an example.

The water collecting tank (103) is a reservoir for collecting non-point polluted water including pollutants generated in a nonpoint pollution source, and may include, for example, a manhole on the road. Such a water collecting tank 103 may be variously provided in a large size, a medium size, a small size, and the like as necessary.

Of course, it is preferable that the fallen leaves, the cut trees and the like are filtered by a screen member including a grating having a grating shape before being introduced into the water collecting tank 103.

The water collecting tank 103 is roughly a hexahedron and has an inlet 103a through which non-point polluted water flows, an outlet 103b through which non-point polluted water is treated and discharged, a stationary water inlet 135 that transports reverse water containing pollutants, And an opening or the like through which the driving member 151 and the like can be installed as required and the cleaning and replacement of the filtration unit 150 and the cleaning of the inflow bath 110, the treatment bath 120 and the reverse osmosis 130 And a manhole (not shown) for the user.

The water collecting tank 103 is preferably divided into an inflow bath 110 and a treatment bath 120 and a reverse osmosis bath 130. It is preferable that a controller 170 described later having a waterproof and dustproof function is accommodated as required.

The inflow tank 110 is composed of an inflow tank partition wall 113 through which inflow water flowing in the inflow port 103a and the inflow port 103a is guided to the treatment tank 120 to induce stable flow.

The treatment tank 120 has a treatment tank partition 123 separated from the inflow tank 110 and a treatment tank inflow port 125 formed below the treatment tank partition wall 123 and formed below the inflow tank 110 And the discharge port 103b through which the processed waste water is discharged above the water collecting tank 103 or the treatment tank partition wall 123 is connected to the storm water to discharge the treated water to the river or the like. When excessive inflow of non-spotted polluted water into the inflow bath 110 or failure of the filtration unit 150 of the treatment bath 120 or inflow water exceeding the processing load is introduced into the inflow bath 110, And an overflow inlet 103a formed therethrough.

The contaminants generated in the course of backwashing the contaminants collected in the filtration unit 150 and a part of the water in the treatment tank 120 or the inflow tank 110 can flow downward by their own weight in the lower side of the treatment tank 120 A reverse water discharge port 127 is formed so as to pass therethrough.

The filtration unit 150 is coupled to the middle area of the treatment tank 120, so that the pollutant can be collected in the course of the non-point polluted water flowing from the lower side to the upper side.

With this structure, the method of collecting the contaminants in the filtration unit 150 of the treatment tank 120 can be said to be an upflow filtration method since the flow is maintained from the lower side to the upper side. That is, in the course of filtration, the flow of water becomes a natural flow from the upper side to the lower side in the course of backwashing the contaminants collected in the filtration process from the lower side to the upper side.

That is, the water flows into the treatment tank 120, and the contaminated water in the filtration process flows in the following two directions. First, the polluted water flows from the lower side of the treatment tank 120 to the upper side and is collected in the pores of the floating filter medium layer 152. The treated water treated and treated with the pollutant flows to the river or the like through the discharge port 103b. , The contaminated water including the contaminants in the backwashing process is spontaneously dropped into the reverse osmosis tank 130 by the opening / closing valve 157 that opens the reverse water wash water outlet 127 in the treatment tank 120. The polluted water including pollutants falling into the reverse osmosis tank 130 is transferred to the wastewater treatment plant through the wastewater water pipe by the reverse water wash pump 133.

The waste water tank 130 is disposed below the treatment tank 120 and is disposed in the treatment tank 120. The waste water tank 130 is disposed at a lower portion of the treatment tank 120, For example, as shown in FIG. 1, it is possible to transfer the reverse water to the waste water transfer pump 133 through the wastewater pipe to the wastewater treatment plant. The reverse water transfer pump 133 may include an underwater pump type and may transfer the reverse water collected from the plurality of reverse osmosis chambers 130 to the reverse osmosis transfer pump 133 through the reverse osmosis water inlet 135 opened at the lower side It is possible.

The filtration unit 150 includes a drive member 151, a floating filter medium layer 152 formed of floating filter media 152a, a filter lifting member 154, a separating member guide 154a, a collecting material separating net 155, A filter medium lowering limiting member 156, and an opening / closing valve 157.

The driving member 151 is provided in various forms and is coupled with the on-off valve 157 to enable the on-off valve 157 to operate. In one embodiment, the driving member 151 is driven by electric, pneumatic, And a drive shaft 151b which is coupled with the drive cylinder 151a and can be elevated. The driving member 151 includes a known motor and a speed reducer, and may include power transmission means such as a shaft, a chain, or the like for transmitting the power of the motor or the like to the on-off valve 157.

It is preferable that the floating filter medium 152a includes a spherical synthetic resin whose diameter changes according to the water depth and which has a specific gravity lower than that of water and floats in water. The floating filter medium 152a may be formed of a foamed resin such as polypropylene (PP) or polyethylene. It is preferable that such material is not porous.

The specific gravity of the float filter medium 152a is preferably less than 0.1, more preferably less than 0.1, and still more preferably 0.02 or more and less than 0.1.

The compression strength of the floating filter medium 152a is preferably 1 kg / cm2 or less, and more preferably 0.5 kg / cm2 or more and less than 1 kg / cm2.

In addition, when the floating filter medium 152a continuously expands and contracts in accordance with a change in the depth of water, it is preferable that the filter medium is repeatedly compressed to have a permanent deformation rate of 10% or less.

In this range, the floating filter medium 152a works more efficiently and the volume of the floating filter medium 152a is changed (diameter change) while repeatedly contracting and expanding according to the depth of the water, The material can be broken up very efficiently and separated.

When the floating filter medium layer 152 is formed of the same number of floating filter medium materials 152a having such a property, the depth of the restraint limiting member 154 (see, for example, 'H1' 'H2' 'H3' The height of the floating filter medium layer 152 (see, for example, 'h1' 'h2' 'h3' in FIG. 6A) is different.

7 and 8, the filtration efficiency of the floating filter medium layer 152 or the floating filter medium 152a and the variation in the volume of the filter medium due to the nature of the floating filter medium 152a are the same.

The restraint restricting member 154 includes a net having voids and meshes smaller than the spherical diameter of the floating filter medium 152a so as to restrict floatation of the floating filter media 152a layered on the lower side, And the wall of the treatment tank 120 so as to have strength enough to withstand buoyancy. The restraint limiting member 154 is provided at its four corners with a separating member guide 154a for guiding the collecting material separating net 155 which is coupled with the driving member 151 and moves up and down have.

The collecting material separating member is disposed below the recharge up / down restricting member 154, and moves up and down in conjunction with the opening / closing valve 157 to move the flocculated material 152a and the floating filter material 152, A trapping material separating net 155 as shown in FIG. 3 including a net made of a mesh or a mesh having pores that are three to five times larger than the diameter of the floating filter medium 152a bonded to the member 151 And vibration means such as a vibration motor and a vibrator that are disposed in the floating filter medium layer 152 and provide vibration in the course of backwashing the flocculated contaminants trapped between the floating filter media 152a. That is, the collecting material separating net 155 is coupled to the driving member 151 at the center, and four corners can be coupled to the separating member guide to move up and down.

With this structure, not only the opening / closing valve 157 but also the collecting material separating member can be moved up and down by the lifting and lowering of the driving member 151 by the lifting and lowering of the driving member 151, The filtering medium 152a and the agglomerated collecting material are cut and broken to effectively separate the floating filter medium 152a and the collecting material and the collecting material to effectively collect the backwashing liquid 152a due to the self weight of the collecting and separated collecting materials, The polluted water can be effectively discharged into the water tank 130.

Further, even if there is no collecting material separating member including the collecting material separating net 155, it is possible to repeatedly control the opening and closing valve 157 repeatedly up and down in accordance with the set time so as to repeat the collecting material in the treating tank 120 So that the control unit 170 can control the separation of the collected particulate matter and the floating filter medium 152a between the floating filter medium layers 152.

The filter media lowering restricting member 156 is coupled to the upstream of the reverse water discharge outlet 127 so that the floating filter medium 152a is discharged from the treatment tank 120 through the reverse water discharge outlet 127 by the contaminated water, 130). ≪ / RTI >

The opening and closing valve 157 moves downward to the reverse water discharge port 127 to open the backwash outlet 103b and this movement force is provided by the driving member 151 and is coupled to the driving member 151 .

When a large amount of contaminants are collected in the floating filter medium layer 152 in the treatment tank 120, a backwash process is performed. This backwashing process is preferably performed by the sensor 160 and the control unit 170, which will be described later.

That is, when a large amount of contaminants are collected in the floating filter medium layer 152 of the treatment tank 120, a difference in flow rate between the inflow water and the influent water is detected, or a sensor The control unit 170 determines when the filtration efficiency in the filtration unit 150 is lowered and backwashes based on the result detected by the flow rate sensor 160 (for example, a flow sensor or a sensor using a head difference) Can be performed.

In this backwashing process, according to the present invention, a process in which contaminants collected and accumulated in the floating filter medium layer 152 more effectively than the prior art are cut, broken and separated will be described with reference to FIG. 6B.

6B is a process in which filtration is performed in the floating filter medium layer 152 with the flow of non-point polluted water flowing upward from the bottom of the treatment tank 120. As the pollutant is gradually collected in the air gap between the floating filter media 152a The air gap between the floating filter media 152a gradually decreases and the flow rate of the discharged air decreases, or a difference in head between the floating filter medium layer 152 and the floating filter media 152 is increased. Based on the detection result of the sensor 160 for detecting the decrease in the flow rate or the head difference, the controller 170 determines the point of time reversed by the decelerated flow velocity and head difference. Although the diameter of the floating filter medium 152a shown in FIG. 6B is denoted by 'd1' equal to the diameter of the floating filter medium 152a shown in FIG. 6A, the diameter of the floating filter medium 152a shown in FIG. 6B is larger because the water depth is lower than that shown in FIG. .

When the drive unit 151 is lowered by the control unit 170 and the drive shaft 151b is lowered and the drive shaft 151b is lowered when the drive unit 151 is lowered, the trapping material separation net 155 and the on- 157 also descend and the reverse water discharge port 127 at the lower side of the treatment tank 120 is opened to discharge the contaminated water contained in the treatment tank 120 to the lower side. 6B, when the depth of the treatment tank 120 changes from 'H1' to 'H2' in FIG. 6A and the opening / closing valve 157 and the collecting material separating net 155 are separated from each other by a predetermined distance The floating filter medium 152a descends and the volume of the floating filter medium 152a gradually increases and the floating filter medium 152a and the floating filter medium 152a As the pore between the pores changes, the aggregated trapped material is destroyed. At the same time, as the trapping material separating net 155 moves, the floating filter medium 152a and the trapping material therebetween are moved downward in the same manner as the gel-like product, And the trapping material between the floating filter medium 152 and the floating filter medium 152a and the floating filter medium 152a is broken, cut and separated.

The expansion force of the floating filter medium 152a, the change of the buoyancy, the change of the water depth, the change of the flow velocity, and the downward force of the collection material separating net 155 act on the floating filter medium layer 152 and the collecting material, It is possible to efficiently separate the aggregate and aggregate particles existing between the pores of the floating particles 152 from the floating particles 152a effectively and to break the particles into small particles to break them,

Such trapping material is discharged to the reverse osmosis tank 130 while being sedimented together with the treated water by its own weight, so that the air gap of the floatation filter medium 152a can be kept very constant, so that the filtration efficiency can be maintained stably through backwashing. That is, the backwash efficiency of the floating filter medium layer 152 can be greatly increased, and the service life of the floating filter medium 152a can be maintained for a long time.

Therefore, according to the present invention, it is possible to provide a non-point pollution source abatement device capable of quickly and efficiently back-up the collected substances trapped in non-point pollutants.

In addition, it is possible to provide a nonpoint source pollution reduction device that is simple and convenient to use.

In addition, in the upflow type flow, the filtration efficiency is improved by filtering the non-point pollutants using the floating filter media and effectively backing up and separating the self weight of the non-point pollutant and the aggregated material by the downflow type flow, It is possible to provide a nonpoint pollution source abatement device capable of maintaining the service life of the filter material for a long time.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. will be. The scope of the invention will be determined by the appended claims and their equivalents.

100: pollutant abatement device 103: water collecting tank
103a: Inlet port 103b: Outlet port
103c: Overflow inlet
110: inlet tank 113: inlet tank partition
120: Treatment tank 123: Treatment tank barrier
125: Treatment tank inlet 127: Station drainage outlet
130: Reverse osmosis 133: Reverse osmosis transfer pump
135: station taxi
150: filtration unit 151: driving member
151a: drive cylinder 151b: drive shaft
152: floating filter medium layer 152a: floating filter medium
154: female restraining restricting member 154a: separating member guide
155: Collection material separation net 156: Filter material lowering limiting member
157: opening / closing valve
160: sensor 170:
H1, H2, H3: Depth h1, h2, h3: Height of floating media layer

Claims (7)

A nonpoint source reduction apparatus for reducing pollutants generated in a nonpoint source,
An inlet port communicating with an inlet through which the non-point polluted water including pollutants generated from the non-point pollution source flows; an outlet communicating with the inlet port downstream to discharge the treated pollutant and discharging the treated water; A collecting tank partitioned by a treating tank having a filtration unit capable of backwashing the collecting material and a reverse tank communicating with a lower side of the treating tank to receive the collecting material backwashed in the treating tank,
Wherein the filtration unit comprises a floating filter material layer formed of a plurality of floating filter materials so as to form voids capable of collecting the contaminants received in the treatment tank and transported therefrom; An open / close valve for opening and closing a reverse water discharge port through which the collecting material is discharged so as to be discharged into the reverse osmosis tank when the collection material is backwashed, and a driving member for providing a driving force to the opening / ,
The floatation filter material is elastically deformable by water level fluctuation during filtration of contaminants by filtration of contaminants by floating in water, and has a specific gravity in a range of 0.02 or more to less than 0.1, a weight of more than 0.5 kg / / Cm < 2 >. The method according to claim 1,
The filtration unit,
And a trapping material separation net having a trapping material separating net that is provided in a lattice shape and is engaged with the driving member and disposed below the trapping restraining limiting member and separates the trapping material and the floating filter material into a lattice shape while descending along the driving member upon backwashing Wherein the non-point source depletion device further comprises a member. delete The method according to claim 1,
And a control unit for separating the trapping material and the floating filter material, which are agglomerated between the floating filter medium layers, by controlling the opening and closing valve so that the opening and closing valve can be repeatedly elevated and lowered intermittently in order to back up the trapping material in the treatment tank Wherein the nonpoint source depletion device comprises: 3. The method according to claim 1 or 2,
Wherein the floating filter medium comprises a spherical shape and has a permanent strain of 10% or less. delete delete

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