KR102078387B1 - Reduction facility of non-point pollutants using filter of fibrous filtration type - Google Patents

Abstract

The present invention relates to a non-point pollution treatment facility using a fibrous filtration type filter. The non-point pollution treatment facility using the fibrous filtration type filter includes: a pretreatment tank having a screen tank in the upper part in one side and divided into the screen tank and an overflow unit by having a dead water transfer pump in the lower part of the inside, wherein a treated water inflow pipe is connected outside in the upper part of the screen tank across a first opening and closing valve; a filter tank having an acid radical pipe and multiple fibrous filters enclosed by mesh inside, wherein one side of the filter tank is divided into the pretreatment tank and the overflow unit and the pretreatment tank and the overflow unit are connected across a second opening and closing valve in the lower part; an ultraviolet sterilization device connected from the outside of the filtration tank to the inside of the filter tank; and a reverse water tank connected to the filter tank across a third opening and closing valve on one side of the upper part and including a reverse water pump in the lower part, wherein a discharge pipe is connected to the outside across a fourth opening and closing valve on the other side of the upper part. The non-point pollution treatment facility is formed in order of the screen tank, the pretreatment tank, the filter tank, and the reverse water tank. The non-point pollution treatment facility uses bark from a palm tree having excellent filtration effect as a fibrous filter in the filter tank and installs the fibrous filter in the mesh at the same time. So, the non-point pollution treatment facility can prevent a loss and a blockage of the filter and obtain excellent filtration efficiency of treated water such as polluted rainwater.

Description

Reduction facility of non-point pollutants using filter of fibrous filtration type}

The present invention relates to a non-point pollution reduction facility using fibrous filtration media, and more particularly, to a plurality of fibrous layers enclosed by a metal network in order to improve filtration efficiency in the filtration tank of a non-point pollution reduction facility consisting of a pretreatment tank, a filtration tank, and a backwash water tank. The present invention relates to a non-point pollution reduction facility using fibrous filtration media with media installed.

Nonpoint source is a source of pollutants unspecified from an unspecified place such as a city, road, farmland, construction site, etc. Most of it flows into surface water with surface water during rainfall. It occurs unspecified in a wide range of places and fluctuates with time.

Recently, as interest in non-point pollution management has increased, related organizations such as the Ministry of Environment have been making efforts to investigate the current state of non-point pollution sources including rainfall runoff and establish treatment plans. Non-point pollution reduction facilities to prevent the ingress of non-point pollution into the water system include reservoirs, vegetation waterways, infiltration ditches, and filtration facilities. The most widely used process for a long time is a filtration treatment facility using granular filter materials. .

Specifically, non-point pollution abatement facilities are facilities that remove or reduce water pollution-causing substances emitted from nonpoint sources as provided in Table 6 of the Enforcement Regulations on the Act on the Conservation of Water Quality and Ecosystems. Non-point source reduction facilities are divided into three types, low impact development techniques, natural type and device type. Types of natural types include storage facilities, infiltration facilities, artificial wetlands, and vegetation facilities. Types of device types include filtration type, fire type, screen type, flocculation, and biological treatment facilities.

Filtration in dual filtration non-point pollution abatement facilities is most often used when urbanization is highly advanced and impermeable, and the site is limited. Filtration is high, but there is a problem that the solid material is re-spilled during heavy rainfall at the same time the loss head increases due to the blockage of the filter media during operation. This may cause a problem of increased maintenance costs such as backwashing of media and replacement of media. Therefore, nowadays, many up-flow filtration facilities are used, and the selection of suitable media, the configuration of the appropriate system, and the proper performance evaluation can achieve the reduction of nonpoint source.

The treatment scale of nonpoint pollution abatement facilities should be able to convert rainfall to cumulative runoff and be able to handle at least 5mm of rainfall. At this time, the cumulative runoff refers to the actual storm runoff, excluding the subterranean penetration and the amount of evapotranspiration.

The criteria for nonpoint pollution abatement facilities are defined by the “Installation and Management of Nonpoint Pollution Abatement Facilities, Operation Manual (Ministry of Environment, 2014)”, and the linear velocity of the filter tank is less than 20m / hr, the median layer thickness is about 60cm, and the foamed fibrous media In the case of, it is recommended to be around 30cm. In case of filter media, backwashing is possible, and the head of loss should be reduced to the initial value after backwashing. In addition, the annual SS removal efficiency should be 80%, and the head of loss should not exceed 10cm, the permeability should be 1.5 ~ 2 times the linear speed, and there should be almost no blockage and head of loss even in the case of solid load up to 8kg / m ² . do. In the case of backwashing, the backwashing should be carried out within 48 hours after the end of the rainfall, even if the cumulative rainfall is 10mm. The air cleaning + treated water method is generally used. (Reference criteria and technology trends related to non-point pollution reduction facilities (2017), Korea Water Resources Association)

Filtered non-point pollution abatement facilities are a type of equipment, and the design of the filter facility should determine the storage capacity, residence time, and filter media based on the removal efficiency, construction cost and maintenance cost of the facility. In addition, the filter area and depth (height) are designed in consideration of the amount of water passed through the filter medium. However, it is not easy to apply in the field because detailed design criteria are not clear. (Reference: Treatment Efficient of Non-Point Source Pollutants Using Modified Filtration System, 2011, Korean Journal of Wetlands, Kang Hee Man, Choi Ji Yeon, Kim Hyung Kim, Actor Geun)

In 2014, the “Installation, Management, and Operation Manual of Non-point Pollution Reduction Facilities” was revised, requiring the installation of backwash facilities for filtration facilities. Therefore, backwashing should be carried out within 48 hours after the end of the rainfall, and after the backwashing, the wastewater should be treated in conjunction with pipe or conduit. (Reference Criteria and Technology Trends for Non-point Pollution Reduction Facilities (2017), Korea Water Resources Association)

Non-point pollution related research has mainly been carried out using various media. The biggest consideration in the design and operation of filtration devices for non-point pollution reduction is that the filter line velocity of the device is significantly reduced due to median blockage (Warnaars et al., 1999; Bouwer, 2002). Occlusion of media layers is an important factor in determining the life of media when backwashing by power is difficult (Siriwardene et al., 2007). In addition, the increase in head loss is directly related to the amount and size of SS to be treated and the size of the media (Boller and Kavanaugh, 1995).

Accordingly, Jusoh et al. (2007) judged the time when the head layer was blocked and the loss head increased to a certain level (240-300 mm), or the time when the runoff turbidity increased above a certain level (1.00 NTU) as the life of the filtration facility. It was.

Sand has been the most studied media for filtration nonpoint pollution abatement facilities, and other media have recently been tried. Northern filter media (www.northern filtermedia.com) in the US uses sand, quartz, Mn green sand, zeolite, etc. for non-point pollution filtration facilities, and Kim Tae-kyun (2009) uses Perlite and Resin, Ping and Yajun. (2010) conducted research on sand soil, slag, ceramsite, etc.

The present invention has been made to improve the above-mentioned problems, the purpose is to construct a non-point pollution reduction facility, such as pre-treatment tank, filtration tank and backwash water tank, to filter the treated water flowed in from the pretreatment tank and treated Discharges non-point source and odor-free removal water through the process of washing, and reduces the non-point pollution using fibrous filtration media which makes the treatment of filtration more efficient by installing a fibrous media surrounded by metal mesh in the filtration tank. In providing facilities.

In order to achieve the object as described above, in the non-point pollution reduction facility using the fibrous filtration media of the present invention, a screen tank is installed at an upper portion of one inside, and a treatment water inlet pipe is disposed between the first on / off valves above the screen tank. A pretreatment tank connected to the outside and placed in the lower portion, and having a stagnant water transfer pump installed in the lower portion of the inner space; A filtration tank having a plurality of fibrous media and an diffuser surrounded by a metal mesh therein and partitioned into one of the pretreatment tank and the overflow at one side thereof and connected to each other with a second on / off valve interposed therebetween; An ultraviolet sterilizer connected to the filter tank from the outside of the filter tank; And a back washing pump connected to the filtration tank and a third opening / closing valve between one side of an upper portion, and a backwash pump installed on a lower portion of the inner portion, and a backwash tank connected to the outside with a discharge pipe interposed between the fourth opening and closing valves on the other side of the upper portion. It is characterized by including;

In addition, the fibrous media is preferably composed of palm bark.

In addition, the pretreatment tank is divided into two sections, a first pretreatment tank and a second pretreatment tank, and the first pretreatment tank and the second pretreatment tank are connected with a fifth open / close valve interposed therebetween, and the second pretreatment tank is divided into a filtration tank and an overflow. It is preferable that the lower opening and closing valve is connected to each other.

According to the non-point pollution reduction facility using the fibrous filtration media of the present invention, the palm tree bark having excellent effect of filtering the fibrous media in the filtration tank in the non-point pollution reduction facility consisting of a screen tank, a pretreatment tank, a filtration tank, and a backwash tank is used. At the same time, by installing the fibrous media in the metal mesh, the efficiency of filtration of treated water such as rainwater that is contaminated by preventing the media and the loss of media is prevented.

In addition, by installing the screen tank in the pretreatment tank in the non-point pollution reduction facility having the above configuration, there is an effect of maximizing the pretreatment effect of the treated water before filtration in the filtration tank.

In addition, when the filtered treated water is discharged into the sewer pipe by using an ultraviolet sterilizer during the filtration of the treated water in the filtration tank, the odor is effectively removed and discharged.

1 is a front cross-sectional view of a non-point pollution reduction facility using a fibrous filter medium according to the present invention.
2 is a cross-sectional plan view of a non-point pollution reduction facility using a fibrous filter medium according to the present invention.
Figure 3 is a cross-sectional side view of the filtration tank of the non-point pollution reduction facility using a fibrous filter medium according to the present invention
Figure 4 is a schematic diagram of an experimental apparatus for a non-point pollution reducing facility using a fibrous filter medium according to the present invention
5 is a real photograph of each part of the experimental apparatus of FIG.
6 is a graph of the loss head by the depth of the filter media according to the filter line velocity
7 is a graph of the head (filtration line speed 10m / hr) according to the filtration time
8 is a graph of the loss head (filtration line speed 10m / hr) according to the filtration time
9 is a graph of SS removal rate, cumulative SS removal rate, filter bed cumulative SS load and loss head (filtration line speed 10m / hr) according to the filtration time
10 is a graph of the head (filtration line speed 15m / hr) according to the filtration time
11 is a graph of the loss head (filtration line speed 15m / hr) according to the filtration time
12 is a graph of SS removal rate, cumulative SS removal rate, filter bed cumulative SS load and head loss (filtration line speed 15m / hr) according to the filtration time
13 is a graph of the head (filtration line speed 20m / hr) according to the filtration time
14 is a graph of the loss head (filtration line speed 20m / hr) according to the filtration time
15 is a graph of SS removal rate, cumulative SS removal rate, filter bed cumulative SS load and loss head (filtration line speed 20m / hr) according to the filtration time
Figure 16 shows the head and loss head according to the time before and after backwashing (filtration line speed 40m / hr, backwashing filtered water 20m / hr)
17 shows the head and loss head according to the time before and after backwashing (filtration line speed 40m / hr, backwashing air (3 times-1minute) 10m / hr + filtration water 10m / hr)

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a non-point pollution reducing facility using a fibrous filter medium according to the present invention will be described in detail. The present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only this embodiment to complete the scope of the invention to those skilled in the art and complete the scope of the invention to those skilled in the art It is provided to inform you.

1 is a front cross-sectional view of a non-point pollution reduction facility using a fibrous filtration media according to the present invention, Figure 2 is a plan sectional view of a non-point pollution reduction facility using a fibrous filtration media according to the present invention, Figure 3 is Side cross-sectional view of the filtration tank in a non-point pollution reduction facility using the fibrous filter media according to the present invention.

1 to 3, the non-point pollution reduction facility using the fibrous filtration media according to the present invention is a pre-treatment tank (2) including the screen tank (1), filtration tank (3) and backwash tank (4) Are arranged in a row and connected in series, and the ultraviolet sterilizer 5 is separately connected to the filtration tank 3.

The pretreatment tank 2 is provided with a screen tank 1 as a separate space on one wall of the inside, and the inlet pipe 6 is externally provided on the screen tank 1 with a first opening / closing valve 7a interposed therebetween. The treated water, such as rainwater contaminated by being connected to one wall of the pretreatment tank 2, is introduced into the screen tank 1 once, and the introduced treated water is divided into the pretreatment tank 2 and the overflow and the pretreatment tank 2 Go to). In addition, a stagnant water transfer pump 8 is installed at the bottom of the pretreatment tank 2 to treat stagnant water remaining in the pretreatment tank 2 because the stagnant water transfer pump 8 is no longer introduced into the treated water. Transfer to the outside is stored in the temporary storage tank 15 or discharged to the sewage pipe (16).

In addition, the pretreatment tank 2 is divided into two first pretreatments 2a and a second pretreatment tank 2b with a wall in the middle in order to increase the efficiency of the pretreatment. The on-off valve 7b is installed to allow the treated water to move between the first pretreatment 2a and the second pretreatment tank 2b. In this case, the stagnant water transfer pump (at the bottom of the first pretreatment tank 2a) is provided. If 8) is installed, another stagnant water transfer pump 9 is installed at the bottom of the second pretreatment tank 2b.

In this way, the pretreatment tank 2 is divided into the filtration tank 3 and the overflow, and the filtration tank 3 when the pretreatment tank 2 is divided into a first pretreatment 2a and a second pretreatment tank 2b. Is divided into a second pretreatment tank 2b and an overflow. The fifth opening / closing valve 7e is provided at the lower portion of the partition wall partitioning the second pretreatment tank 2b and the filtration tank 3.

The filtration tank (3) is provided with a plurality of fibrous media (11) surrounded by a metal mesh 10 side by side in two rows at the top, so as not to be lost while maintaining the shape with the fibrous media (11), pretreatment tank ( The treated water from 2) is filtered through the plurality of fibrous media 11 and then stored in the filtration tank 3. In this way, the treated water stored after removing the contaminants after filtration is additionally filtered by bubble air connected to the bottom of the filtration tank 3 and supplied from the diffuser 12. That is, the diffuser 12 generates air in the form of bubbles in the lower part of the filtration tank 3 to desorb additional filtered and adsorbed contaminants of the treated water stored in the filtration tank 3, Float to the top. The metal mesh 10 is composed of a wire mesh or an aluminum mesh.

In addition, an ultraviolet sterilizer 5 installed outside is connected to the inside of the filtration tank 3 to remove odors and the like of the treated water stored in the filtration tank 3 by being filtered by the fibrous media 11. do.

The backwash tank (4) is connected to the filtration tank (3) with a third open / close valve (7c) provided on one partition wall partitioned therebetween, and a fourth open / close valve (7d) on the opposite backwash tank (4) wall. The discharge pipe 14 is connected with the gap therebetween, and finally, the treated water from which the pollutant is removed through the discharge pipe 14 flows into the sewer pipe 16. At the bottom of the backwashing tank 4, a backwashing pump 13 for backwashing the treated water which has been filtered out of the filtration tank 3 is provided.

Next, the non-point pollution filtration process of the non-point pollution reduction facility using the fibrous filtration media of the present invention configured as described above will be described.

First, when rainwater, such as rainwater containing contaminants as a non-point pollutant, flows into the screen tank 1 through the inlet pipe 6, heavy pollutants such as sand are first precipitated and the treated water overflows. The process proceeds to the first pretreatment tank 2a of the pretreatment tank 2.

Then, the treated water which has passed to the first pretreatment tank 2a is once again removed by sedimenting the pollutants secondly, and the treated water from which the pollutants have been removed is passed through the second opening / closing valve 7b to the second settling tank 2b. Goes.

Thereafter, the second settling tank 2b once again removes contaminants by tertiary again, and the treated water from which the contaminants are removed is passed to the filtration tank 3 by an overflow.

Here, the treated water remaining in the second pretreatment tank 2b is transferred to the first pretreatment tank 2a by the stagnant water transfer pump 9, and the treated water remains in the first pretreatment tank 2a. The stagnant stagnant water is transported by the stagnant water transfer pump 8 and stored in the temporary storage 15 or discharged through the inlet pipe 16 as described above.

After that, the treated water passed to the filtration tank 3 is secondarily filtered by the air bubbles supplied from the diffuser 12 by removing the contaminants from the plurality of fibrous media 11 surrounded by the metal mesh 10. It is removed and is passed to the backwash water tank 4 through the 3rd opening / closing valve 7c in the state which became the treated water with almost no pollutants. At this time, the odor remaining in the treated water is almost eliminated by the ultraviolet sterilizer (5) connected to the filter tank (3).

Then, the treated water which has passed to the backwash tank 4 is transferred to the filtration tank 3 again by the backwash water pump 13, and once again returned to the backwash tank 4 in the state of completely removing contaminants, The treated water from which the pollutants are almost completely removed flows into the sewer pipe 16 through the discharge pipe 14 by opening the fourth on / off valve 7d.

On the other hand, if stagnant water remains in the filtration tank 3 or the backwash tank 4 as well as the stagnant water remaining in the pretreatment tank 2, the backwash tank 4 is a backwash pump 13 and a third open / close valve 7c. ), The filtration tank (3) is returned to the pretreatment tank (2) through the fifth opening and closing valve (7e) between the second pretreatment tank (2b) and the filtration tank (3), the stagnant water transfer pump (8) as described above (9) is transferred to the temporary storage tank 15 and the sewer pipe (16).

The following shows the results of filtering the treated water, such as rainwater, using a non-point pollution reduction facility using a fibrous filter material using palm tree fibers surrounded by metal mesh, using a non-point pollution reduction facility using a fibrous filtration media of the present invention. An embodiment will be described.

First, the media used in the present invention was tested using fibrous media. Fibrous media is a fibrous media that is made of sheets using palm fiber.

The design physical properties of the media are as follows.

Bulk Density: 222334.8g / ㎡

Permeability: 61.82m / hr

In addition, the experimental apparatus for the non-point pollution reduction facility of the present invention used an acrylic column (50 × 50 × 300mm, 150 × 50 × 800mm) provided with a sampling port and a piezometer as shown in FIGS. 4 and 5. The column is divided into an inflow column and a filtration column to maintain the inflow and outflow steps. Sampling port, piezometer, inflow pump, backwash pump, raw water tank (200L) and stirrer, backwash water tank (200L) were used as other accessories.

The treated water was injected into the inflow column at a predetermined filtration line speed, and the fibrous material was filled to a depth of 30 cm, and the treated water was introduced into the lower part of the filtration column, and then the effluent was discharged from the top of the filter bed of the filtration column. At this time, the level of the inflow column and the outflow level of the filtration column were kept constant. The piezometer level was recorded for each depth of the media layer during the operation. The same experiment was repeated for 50 minutes at 10, 15 and 20m / hr, respectively, and the no-load loss head was calculated according to the filter line velocity.

The results of the filtration experiment of the treated water using the experimental apparatus for the non-point pollution reduction facility of the present invention are as follows.

As a result, the permeability coefficient of the fibrous media was 61.82 m / hr (1.717 cm / sec).

As shown in Fig. 6, the initial filtration line speeds of the fibrous material were set to 10, 15 and 20 m / hr, and each was operated for 50 minutes. At the filter line velocities of 10, 15 and 20m / hr, the loss heads at the depth of 30 cm of the filter media were 0.1, 0.2 and 0.2 cm, respectively.

Next will be described the loss head and SS removal rate according to the operating conditions using the experimental apparatus for the non-point pollution reduction facility of the present invention.

Sediments were collected from nearby rainfall runoff drainage and used to screen particles up to 150μm.

Experimental apparatus for a non-point pollution reduction facility of the present invention used the same apparatus as shown in FIG. The sediment prepared in the influent tank is mixed with the time constant so that the SS concentration is 150 mg / L, injected into the inlet column at a predetermined filtration linear velocity, introduced into the lower part of the filtration column filled with the filter medium, and then at the top of the filter bed of the filtration column. The effluent was discharged. At this time, the level of the inflow column and the outflow level of the filtration column were kept constant. Depending on the conditions, a total of 600 minutes of operation, the piezometer level was recorded for each depth of the media layer according to the specified time, the flow rate was measured, and the SS concentration was measured by collecting influent and effluent samples (Ministry of Environment, 2011). According to the analysis.

The experimental conditions applied were the depth of the filter bed with a depth of 30 cm of the filter bed for the fibrous filter material recommended in <Installation, Management, and Operation Manual of the Non-point Pollution Reduction Facility, 2014>. , 15, and 20 m / hr were presented as experimental conditions.

SS removal rate was calculated by the following equation (1).

Where Rt is the SS removal rate (%) at filtration time t, Co is the average inflow SS concentration (mg / L) during filtration time, and Ct is the outflow SS concentration (mg / L) at filtration time t.

Examination of the runoff flow rate and runoff SS concentration can determine whether the media is blocked. As the SS trapped in the media increases, the media is blocked, resulting in increased head loss and reduced outflow. In addition, in general, as SS accumulates inside the media layer, they play a role of media, thereby increasing the SS removal efficiency. However, if the amount of accumulated SS increases above the SS capture capacity of the media layer, the inflow SS and the captured SS reach breakthrough through which the outflow SS and the effluent flow out, requiring backwashing or replacement of the media layer.

The experimental results are as follows.

Loss head and SS removal rate (filtration line speed 10m / hr)

During 600 minutes of operation, the head of the media layer slightly changed throughout the media layer, as shown in FIG. As shown in FIG. 8, the total head loss slightly increased from 0.1 cm to 0.2 cm after 180 minutes, continued to 0.4 cm after 360 minutes, and then changed to 0.6 cm at 600 minutes.

According to the operating time, the outflow SS concentration was discharged to the initial high concentration and then immediately decreased, and tended to be continuously lowered (Fig. 9 (a)). During operation, the inflow SS concentration was 151.8 ± 1.8 mg / L and the outflow SS concentration was 22.1 mg / L on average (standard deviation 11.5, maximum 53.0 mg / L, minimum 10.0 mg / L). The SS removal rate averaged 85.5% (standard deviation 7.5, highest 93.3%, minimum 65.8%).

At 240 minutes of operation time, the cumulative inflow SS load per unit filter area was 6.0 kg / m2, at which the cumulative SS removal rate was 82.27% (Fig. 9 (b)).

After operation (600 minutes), the total cumulative SS captured in the median layer was 13.2 kg / m2, and the total head of the median layer at this time was 0.6 cm (Fig. 9 (c)).

Inflow cumulative SS load, filter layer cumulative SS load and loss head according to operating time (filter line speed 10m / hr) Item Driving time (minutes) 10 20 30 60 90 120 180 240 300 360 420 480 540 600 Inflow Cumulative SS Load (kg / ㎡) 0.1 0.4 0.6 1.4 2.1 2.9 4.4 6.0 7.5 9.0 10.5 12.0 13.5 15.0 Cumulative SS Load (kg / ㎡) 0.1 0.3 0.5 1.2 1.7 2.3 3.6 4.9 6.3 7.7 9.1 10.4 11.8 13.2 Head (cm) 0.0 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.4 0.4 0.4 0.5 0.6

Loss head and SS removal rate (filtration line speed 15m / hr)

During the operation of 600 minutes, as shown in FIG. 10, the head of the media layer slightly changed throughout the media layer. The total head loss was slightly increased from 0.1 cm to 0.4 cm after 420 minutes, and then changed to 0.5 cm at 600 minutes.

According to the operating time, the effluent SS concentration showed a high concentration at 90 minutes and then decreased, and after 420 minutes, the effluent concentration tended to increase little by little (Fig. 12 (a)>. During operation, the inflow SS concentration was 150.1 ± 3.7 mg / L and the outflow SS concentration was 27.4 mg / L on average (standard deviation of 7.6, maximum of 44.0 mg / L, minimum of 11.0 mg / L). The SS removal rate averaged 81.7% (standard deviation 5.3, highest 92.8%, minimum 70.1%).

At 180 minutes of operation time, the cumulative inflow SS load per unit filter area was 6.5 kg / m2, and the cumulative SS removal rate was 79.4% (Fig. 12 (b)).

After operation (600 minutes), the total cumulative SS captured in the median layer was 18.5kg / m2, and the total head of the median layer at this time was 0.5cm (Fig. 12 (c)>).

Inflow cumulative SS load, filter layer cumulative SS load and loss head according to operating time (filtration line speed 15m / hr) Item Driving time (minutes) 10 20 30 60 90 120 180 240 300 360 420 480 540 600 Inflow Cumulative SS Load (kg / ㎡) 0.2 0.6 1.0 2.1 3.2 4.3 6.5 8.8 11.1 13.3 15.4 17.8 20.1 22.3 Cumulative SS Load (kg / ㎡) 0.1 0.5 0.8 1.7 2.5 3.3 5.2 7.2 9.3 11.2 12.9 14.9 16.8 18.5 Head (cm) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.4 0.4 0.4 0.5

Loss head and SS removal rate (filtration line speed 20m / hr)

During the 600 minutes of operation, the head of the filter bed rose across the filter bed, as shown in FIG. The total head loss was increased from 0.6 cm to 1.0 cm after 300 minutes and then to 1.1 cm at 600 minutes, as shown in FIG. 14.

According to the operating time, the outflow SS concentration tended to decrease gradually from the initial high concentration up to 180 minutes, and then increased gradually thereafter, showing the highest concentration at 600 minutes when the operation was completed (Fig. 15 (a)>). During operation, the inflow SS concentration was 151.8 ± 2.7 mg / L and the outflow SS concentration averaged 28.6 mg / L (standard deviation 7.3, maximum 45.0 mg / L, minimum 14.0 mg / L). The SS removal rate averaged 81.2% (standard deviation 4.9, highest 91.0%, minimum 70.0%).

At 120 minutes of operation time, the cumulative inflow SS load per filtration area was 5.8 kg / m2, and the cumulative SS removal rate was 81.8% (Fig. 15 (b)).

After operation (600 minutes), the total cumulative SS captured in the median layer was 24.6kg / m2, and the total head of the median layer at this time was 1.1cm (Fig. 15 (c)).

Inflow cumulative SS load, filter layer cumulative SS load and loss head according to operating time (filter line speed 20m / hr) Item Driving time (minutes) 10 20 30 60 90 120 180 240 300 360 420 480 540 600 Inflow Cumulative SS Load (kg / ㎡) 0.3 0.8 1.3 2.8 4.2 5.8 8.9 12.0 15.0 17.9 21.0 24.1 27.1 30.1 Cumulative SS Load (kg / ㎡) 0.2 0.6 1.0 2.2 3.4 4.7 7.6 10.2 12.7 15.2 17.7 20.1 22.5 24.6 Head (cm) 0.6 0.7 0.7 0.7 0.8 0.8 0.8 0.9 1.0 0.9 1.0 1.0 1.0 1.1

The following describes the backwashing efficiency.

Experimental apparatus for a non-point pollution reduction facility of the present invention was used the same apparatus as in Figure 5, SS was used as sediment in rainfall runoff drainage of less than 150μm as described above.

Filtration media was used for backwashing media. In order to induce the blockage of the filter media, the sediment prepared in the influent tank was mixed with the time constant so that the SS concentration was 2,000 mg / L, and the fibrous media was filled with 30 cm at a filter linear velocity of 40 m / hr, and injected into the experimental apparatus 3 cm. The operation was continued until the above head was increased. After confirming the head loss, back washing was performed by air and water washing, and water washing using filtered water, respectively.

When washing air and water three times for 1 minute, the filter media layer in which 10m / hr of air is injected into the filtration column is washed, and the stagnant water in the filtration column is drained. The media layer was washed by sprinkling at. When washing with filtered water, the stagnant water in the filtration column was drained and 20m / hr of filtered water was sprinkled on top of the filter bed to wash the filter bed. Afterwards, the influent of 2,000 mg / L of SS concentration was injected into the experimental apparatus at a filter linear velocity of 40 m / hr, and operated until the loss head of 3 cm or more was increased, and the loss head after backwash was examined.

In general, the backwashing of the filtration system is performed by injecting high pressure air from the bottom of the filter bed in the state where the filter bed is saturated with water, and then washing the air and injecting water of high pressure again (Ministry of Environment, 2014). . However, the backwashing of the filtration system in the non-point pollution reduction facility of the present invention is performed by draining the water of the filter bed after air washing and spraying the filtered water in a downward direction above the filter bed. As a result, it is possible to reduce the power cost, equipment cost and backwashing quantity required by using the high pressure pump.

The experimental results are as follows.

-Head loss after backwashing (filter 20m / hr)

Before backwashing, the head loss of the total media layer (30 cm) was 0.9 cm at 5 minutes of operation time, and the head of the head was increased to 4.5 cm at 900 minutes of operation time. Thereafter, when backwashing was performed under the condition of filtered water 20m / hr, the head loss of the entire media layer was 1.0 cm at 5 minutes of operation time after the backwashing, and all of the initial heads before the backwashing were recovered. After backwashing, the loss head at 900 minutes of operation time was 4.7 cm, representing an approximation to the loss head at 900 minutes of operation time before backwashing.

-Head loss after backwashing (air (3 times) 10m / hr + filtration water 10m / hr)

Before 5 minutes of backwashing, the head loss of the total media layer (30 cm) was 0.6 cm at 5 minutes of operation time and increased to 3.1 cm after 900 minutes. Then, after backwashing at 10m / hr for 3 minutes and 10m / hr of filtered water for 1 minute, the head loss of the entire filter bed was 0.8 cm at 5 minutes of operation time, and almost recovered the initial head before the backwashing. . After backwashing, the loss head at 900 minutes of operation time was 3.5 cm, as shown in FIG. 17, indicating that the fibrous material recovered the filtration performance through backwashing.

The conclusion of the filtration experiment using the experimental apparatus for the non-point pollution reduction facility of the present invention is as follows.

-Loss head of filter

When there was no SS in the influent, the no-load loss head of the fibrous material was 0.2 cm at 20 m / hr of filter wire velocity, respectively.

-Total loss head of facility when design flow rate flows in

For the design flow inflow, the total head loss of the facility was calculated as the sum of the head losses for the inflow and outflow pipes and the media. If the inlet pipe is designed to be at an inflow velocity of 0.3 m / s or less (filter design facility inlet pipe design in the 'Installation, Management, and Operation Manual of Non-point Pollution Reduction Facilities' (Ministry of Environment, 2014.04)), the inflow loss is 0.2 cm When the outlet pipe is also designed with the same diameter, the outflow loss is 0.2cm. As the result of the filter head loss, the fibrous filter remained less than 0.2cm at the filter line velocity of 20m / hr, the total head loss of the facility could be expected to be 0.6cm, which is the sum of the loss heads for the inlet / outlet pipe and the filter bed.

Permeability coefficient (filtration rate)

The permeability coefficient of the fibrous material was 61.82 m / hr, which was 3.09 times that of the design filter wire velocity of 20 m / hr.

-Head loss of filter media by solid load

When using the fibrous material of this filtration system, the head loss is 0.6, 0.5 and 1.1 cm when the cumulative SS load is 15.0, 22.3 and 30.1 kg / m2 at 600 minutes of operation time, respectively. In addition, the head loss increased relatively as the line velocity increased.

SS treatment efficiency according to filtration line speed

The filtration system of the non-point pollution reduction facility of the present invention has an average SS removal rate of 15.0, 22.3 and 30.1 kg / m2 with cumulative inflow SS loads at 600 minutes of operation time at 10, 15 and 20 m / hr, respectively. 85.5%, 81.7% and 81.2%, respectively, could achieve more than 81.2% SS removal. Judging from the results, it is judged that all of the used media can be used for a long time, and through this, the annual treatment efficiency of 80% or more can be achieved.

-Reduce the lost head after backwashing

The filtration system of the non-point pollution reduction facility of the present invention has a loss head after performing backwashing under all conditions when backwashing under two conditions of 20m / hr filtered water and 10m / hr of treated water 10m / hr three times for 1 minute in air. Reduced to initial loss head. In addition, after the backwash operation, the removal efficiency and the loss head of pollutants such as before backwashing were generated. Therefore, if the proper cycle is backwashed, annual treatment efficiency of 80% or more can be achieved.

Design factors for optimal fiber filtration facilities

Putting together the results of the above research according to the present invention, the suitable filtration conditions of the fibrous filter facility is the filter linear velocity of 20m / hr, the median layer thickness is 30cm.

The backwash conditions of the fibrous media can be sufficiently effective backwashing by washing the filtered water 20m / hr for 3 minutes and the 10m / hr of air 3 times + 10m / hr of treated water 3 minutes. However, considering the economic efficiency such as operating cost at 20m / hr filtration line speed and 30cm thickness of media for stable treatment, the optimal backwashing factor is 20m / hr for 3 minutes.

Although the non-point pollution reduction facility using the fibrous filtration media of the present invention was described with reference to the drawings, the present invention is not limited by the embodiments and drawings disclosed herein, and the scope of the technical idea of the present invention. Of course, various modifications can be made by those skilled in the art.

1: Screen Tank 2: Pretreatment Tank
2a: first pretreatment tank 2b: second pretreatment tank
3: filtration tank 4: backwash tank
5: ultraviolet sterilizer 6: inlet tube
7a: 1st switching valve 7b: 2nd switching valve
7c: 3rd open / close valve 7d: 4th open / close valve
7e: 5th open / close valve 8,9: stagnant water transfer pump
10: metal mesh 11: fibrous media
12: diffuser 13: backwash pump
14: discharge pipe 15: temporary storage tank
16: sewage pipe

Claims (3)

A screen tank is installed at an upper portion of one inside, and a treatment water inflow pipe is connected to the outside of the screen tank with a first opening / closing valve interposed therebetween. Compartmentalized pretreatment tanks;
A filtration tank having a plurality of fibrous media and diffuser pipes surrounded by a metal mesh therein and partitioned into one of the pretreatment tank and the overflow at one side thereof and connected to each other with a second on / off valve interposed therebetween;
An ultraviolet sterilizer connected to the filter tank from the outside of the filter tank; And
A backwash water tank connected to the filtration tank and a third open / close valve at one side of an upper portion, and a backwash pump installed at a lower portion of the inner portion, and a backwash tank connected to the outside with a discharge pipe connected to a fourth open / close valve at the other side of the upper portion;
It is made, including,
The fibrous media is composed of palm bark, a floating fibrous media is made of a sheet made using the fiber of the palm bark,
The pretreatment tank is divided into two, a first pretreatment tank and a second pretreatment tank, and the first pretreatment tank and the second pretreatment tank are connected with a fifth open / close valve interposed therebetween, and the second pretreatment tank is divided into a filtration tank and an overflow, Non-point pollution reduction facility using a fibrous filter media, characterized in that connected via the second on-off valve. delete delete

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