JP2003193552A - Treatment method for road drainage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method for road drainage for reducing a load of a converged sewage passage, untreated sewage overflowing from a rainwater box, and directly processing the road drainage for ensuring maintenance of a public water area. <P>SOLUTION: In the invention of a first claim, the road drain led from a side-gutter in the road is roughly processed by a floating filtration device 3 and the like to be discharged to the public waters such as a river. The sludge produced from the floating filtration device 3 and the like is discharged to a sewer pipe or processed after a dewatering process. In the invention of a second claim, roughly processed water is retained in a water-bearing pond, while the roughly processed water is finely processed by an advanced water treatment device 8 to be discharged to the public water area such as the river, and the sludge is discharged to the sewer pipe or disposed after the dewatering process. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating road drainage discharged by rainfall on a highway or the like.

[0002]

2. Description of the Related Art Road drainage is currently excluded from sewerage in areas where combined sewerage is installed, and into public water areas such as rivers and lakes in areas where branch sewerage is installed and areas where sewerage has not been developed. However, although the harmfulness of road drainage has recently been pointed out, the only countermeasure is to implement low-performance treatment such as screen filtration in the rainwater discharge of the combined sewer. Therefore, when there is a large amount of rainfall, the sewage mixed with rainwater via the spillway is untreated and released into public water bodies, causing oil balls to occur in the sea area near the city. Moreover, although not surfaced, there is concern about the presence of sewage-derived pathogens in public water bodies.

[0003]

SUMMARY OF THE INVENTION The present invention reduces unloaded sewage that overflows from a rainwater discharge by reducing the load of the combined sewer by separately treating road drainage that has been conventionally excluded to the combined sewer. The aim is to reduce the amount of wastewater and to directly treat road drainage, which has become a problem of toxicity, to protect public water bodies.

[0004]

A method for treating road drainage according to the invention of claim 1 which is made to solve the above problems, comprises:
In the method of treating and removing road drainage by providing a gutter on the side of the road, the road drainage introduced from the gutter is simply treated and the treated water is discharged to public water bodies such as rivers, and the generated sludge is discharged to a sewer pipe. Alternatively, it is characterized by being disposed of after dehydration treatment. The method for treating road drainage according to the invention of claim 2 is a method for removing and treating road drainage by providing a gutter on the side surface of the road, and by providing a water reservoir at the bottom of the road to easily treat the road drainage introduced from the gutter. , The simple treated water is made to stay in the holding pond, and the simple treated water is discharged to a public water area such as a river after advanced treatment, and sludge generated by simple treatment and advanced treatment is discharged to a sewer pipe or dehydrated. It is characterized by being disposed of after. The present invention will be described in detail below together with the embodiments.

[0005]

1 and 2 are flow sheets showing an embodiment of the invention of claim 1, and FIG. 3 is a flow sheet showing an embodiment of the invention of claim 2. First, these flow sheets will explain the overall outline, and then the details.

In the flow sheet shown in FIG. 1, road drainage guided through a screen 2 from a gutter 1 provided on the side surface of a road is simply treated by a flotation filter 3. Treated water (simple treated water) that has been simply treated by the flotation filter material 4 in the flotation filter device 3 is discharged to a public water area such as a river. On the other hand, the generated sludge captured by the floating filter medium 4 is discharged together with water for washing and draining into a sewer pipe or is sent to a dehydration facility for dehydration treatment and then disposed.

The flow sheet of FIG. 2 is provided with a sand filtration device 5 and a simple treatment water tank 6 after the flotation filtration device 3 of the flow sheet of FIG. 1, and is used for simple treatment of road drainage. is there. In this flowsheet,
The treated water that has been simply treated by the levitation filtration device 3 is further filtered by the sand filtration device 5 and then discharged to a public water area such as a river via the simplified treated water tank 6. On the other hand, the sludge generated from the flotation filter 3 and the sand filter 5 is discharged together with water for washing and draining into a sewer pipe, or is sent to a dewatering facility for dewatering and disposal.

According to the second aspect of the invention shown in FIG. 3, the simple treated water is made to stay in the holding pond 7 provided at the lower part of the road, and after advanced treatment by the advanced treatment equipment 8, it is passed through the advanced treatment water tank 9. Discharge to public water bodies such as rivers. On the other hand, sludge generated from simple treatment and advanced treatment should be discharged to the sewer pipe or disposed of after dehydration treatment. In FIG. 3, the flow sheet of FIG. 1 is combined with the retention tank 7 and the advanced treatment device 8, but the flow sheet of FIG. 2 may be combined with the retention reservoir 7 and the advanced treatment device 8. This advanced treatment uses a treatment tank filled with manganese dioxide (combined with ozone) and granular zeolite for road drainage with a large amount of persistent organic substances, and a treatment tank filled with granular zeolite for road drainage with a small amount of persistent organic substances. To use. Since the flow sheet of FIG. 3 includes all the components of FIGS. 1 and 2, a detailed description will be given below along the flow sheet of FIG.

The greatest feature of the present invention resides in a simple treatment device using the levitation filter 3 or the levitation filter 3 + sand filter 5. Most of the expressways are installed elevated, and if a simple processing device is installed under the expressways, it will be possible to perform powerless processing using the head. Also, if it is installed under a bridge on a general road, the same effect will be obtained.

First, when rainfall starts on the road surface, the rain flowing on the road surface falls into the gutter 1 and is collected to be road drainage. Figure 4 shows the results of a survey on the relationship between rainfall intensity and road drainage on rural expressways. When the rainfall intensity is low, the road surface evaporates or partially penetrates underground. Not collected as wastewater. But,
When the rainfall intensity is 0.5 mm / Hr or more, it exceeds about 50% of the theoretical value obtained from the target road area and the rainfall amount, and the drainage amount itself increases, so treatment is required.

As shown in FIG. 3, the road drainage collected in the gutter 1 is subjected to levitation filtration in which a 2 mm screen 2 is used to remove foreign matter such as leaves and the like, and a floating filter material 4 is filled to a height of 0.6 to 1 m. Enter from the bottom of device 3. The specific gravity of the floating filter medium 4 is preferably 0.1 to 0.4 (FIG. 5) in relation to the water washing speed, and any material such as polyethylene or polystyrene that can be adjusted in specific gravity can be used. The particle size of the flotation filter medium should be atypical size of about 5 to 15 mm, and if it is less than 5 mm, clogging will be severe and it will not be possible to cope with high rainfall intensity. Also, if it exceeds 15 mm, the SS detention amount decreases, and again, it is not possible to cope with high rainfall intensity (Fig. 6).

Road drainage entering from the bottom of the flotation filter 3 rises while precipitating substances such as sand having a large specific gravity,
The floating filter medium 4 removes particles of about 20 to 30 μm or more to form simple treated water. The filtration speed is 250m / day or less,
It is preferably 200 m / day or less. Fig. 7 shows the results of investigating the relationship between the filtration rate and the SS removal rate using road drainage 30 minutes after the start of rainfall.
It can be seen that the SS removal rate drops sharply at the boundary of 50 m / Hr. It can be understood that when the filtration rate is 250 m / Hr or less, the substance having a large specific gravity such as sand is removed by the precipitation, but when it exceeds 250 m / Hr, the precipitation effect disappears. When the flotation filtration is continued, the amount of detained SS gradually increases, and the flotation filter material becomes S.
It becomes impossible to capture S and SS of the simple treated water increases.

FIG. 8 shows the relationship obtained by using road drainage 30 minutes after the start of rainfall. The SS detention amount is 5 kg.
/ M ³ exceeds around since it shows a tendency SS removal rate of a simple processing water is decreased, the floating filter media when SS internment amount reaches the 5 kg / m ³ is better to water washing. Of course, when the inflow of road drainage is stopped or when the treatment is no longer required, the floating filter medium is similarly washed.

The water washing is performed by using the simple filtered water accumulated in the upper portion of the flotation filter 3 as washing water, and the downward washing speeds 1 to 5
m / min for 0.2-2 minutes. The cleaning speed and the cleaning time are set in relation to the specific gravity of the flotation filter medium 4, but the principle is that the flotation filter medium 4 can be washed without flowing out by washing, and 1 m / min for the flotation filter medium with a specific gravity of 0.4. × 1.5 minutes,
For a floatable filter medium of 0.1, it is basically 5 m / min × 0.2 min.

The simple treated water thus obtained is subjected to an altitude treatment after the water has accumulated in the water reservoir 7 until the accumulated rainfall after the start of rainfall reaches 2 mm on average on the target road surface. It is discharged as simple treated water, and when the accumulated rainfall exceeds 5 mm, it is discharged without treatment. When the accumulated rainfall exceeds 5 mm, it is discharged without treatment because road drainage at this point is about several mg / L in SS, as shown in Fig. 9, and the water quality improves before treatment is required. It is because it is done. Of course, this simple treated water may be subjected to another simpler treatment by the sand filtration device 5 as shown in FIG. 2, and similarly highly treated or discharged.

FIG. 10 shows the result of conducting a simple treatment experiment by collecting road drainage during the water quality survey of FIG. The filtration rate during the experiment was 2 for levitation filtration (upflow method).
00m / day, sand filtration (downflow method) is 100m / day. As shown in FIG. 10, if the accumulated rainfall is about 2 mm or less, the SS of the simply treated water is reduced to about 20 mg / L or less, which is the standard for SS discharge of general sewage, by just floating filtration. Public water bodies such as rivers can be discharged. Further, as shown in FIG. 2, if the simple treatment using the sand filter 5 together is performed, the SS of the simple treated water is further improved, so that the treated water can be discharged with peace of mind. If the road is in a remote area such as a mountainous area and the SS of road drainage is only about 50 mg / L even when the traffic volume of the vehicle is low and the vehicle is getting off, it is easy to use only levitation filtration and sand filtration from Fig. 10. It is judged that the SS of the treated water can be treated to about 20 mg / L or less, and the treated water can be discharged without any treatment during rainfall, which is economical.

If the above-mentioned simple treatment method is installed under an overpass or under a bridge as shown in FIG. 11, it can be treated by the head except for the power of the air cleaning blower and the water cleaning pump of the sand filter 5, so that the operating power is reduced. Is significantly reduced. In particular, the levitation filtration device 3 requires no power.

Among the simple treated water thus obtained, the simplified treated water in the portion where the accumulated rainfall is 2 mm or less does not reach the water quality standard and is therefore highly treated. In the advanced treatment, a water reservoir 7 is provided to make the quality of the simple treated water uniform and to stabilize the treatment, and the simple treated water is once made to stay and then treated. The amount of the simple treated water that flows into the holding pond 7 is such that the cumulative amount of rainfall on the target road surface is up to 2 mm on average, and therefore, the volume of the holding pond should correspond to this. For example, if the road width is the same as the effective water depth Hm (1000 Hm
If a water reservoir of m) is provided, the depth will be the target road distance L (m) × 2 / (1000H) m.

The simple treated water that has stayed in the water holding pond 7 is basically contaminated water containing 20 mg / L or more as SS, but its properties vary depending on rainfall intensity, rainfall interval, traffic volume and the like. Table 1 shows the water quality of the simply treated water that was continuously and simply treated by the levitation filtration device 3 and stored and homogenized from the beginning of rainfall until the accumulated rainfall reaches 2 mm.

[0020]

[Table 1]

As is clear from Table 1, the easily treated water by the flotation filter 3 contains organic substances such as BOD and COD as well as nutrient salts such as nitrogen in addition to SS. The advanced treatment device 8 in FIG. 3 uses different treatment methods depending on the properties of the simple treated water. An advanced treatment device 8 in which only granular zeolite is filled in the treatment tank, and an air diffuser 10 for air cleaning is provided in the lower part of the packed bed and an aeration device 11 for aeration is provided near the middle of the packed bed.
Mainly removes SS, nitrogen, phosphorus and BOD. On the other hand, the advanced treatment equipment which is filled with granular zeolite in the lower part of the treatment tank, manganese dioxide in the upper part, an air diffuser for cleaning the lower part of the granular zeolite layer, and an ozone supply device in the lower part of the manganese dioxide layer is SS, In addition to nitrogen, phosphorus and BOD,
COD and persistent organic substances are also removed.

When processing is carried out in a processing tank filled with only granular zeolite, the following procedure is carried out. First, BO for NO _x -N be inorganic coagulant and containing the homogenized simple treated water was
When the ratio of D is less than about 3, a hydrogen donor is supplied in the pipe. The inorganic coagulant is iron-based or aluminum-based, and the addition concentration is about 30 to 50 mg / L. This addition concentration depends on the contained SS concentration, but as shown in FIG.
SS concentration of simple treated water (10
Up to about 0 mg / L)
S can aggregate. Further, the hydrogen donor contains NO _x
It is added when the BOD with respect to N is insufficient, but the addition concentration is set to be about 3 with respect to NO _x —N including the BOD contained. The simplified treated water to which the coagulant and hydrogen donor have been added enters the lower portion of the reaction tank while taking in SS and phosphorus in the pipe and aggregating. 20-70mm diameter in the reaction tank
About 2 to 4 m of granular zeolite is filled,
The upper part around the middle part is aerated.

The simple treated water after coagulation enters the reaction tank and is filtered.
Speed: 50-100m / day, SV: 2-3 / Hr conditions
Although it is filtered in the upward flow by the
Most of the mud is removed by sedimentation before reaching the granular zeolite bed.
Almost all of the remaining is captured and removed by the granular zeolite layer.
It When the simple treated water reaches the granular zeolite layer, aeration
In the lower non-aeration zone, which is not done, it is removed by precipitation.
Most of the coagulated sludge that could not be removed and NO_x-N and NH_Four
-N is removed. The non-aerated zone remains anaerobic
For denitrifying bacteria immobilized on the surface of granular zeolite in order to
BOD contained in or pre-added methanol, vinegar
NO using acid as hydrogen donor _x-Convert N to nitrogen and desorb
Suffocation and also NH_Four-N is adsorbed on granular zeolite
Of. In order for these processes to be established, SS and
Filtration rate is involved in removing coagulated sludge containing phosphorus
And also NO_x-N and NH_Four-SV to remove N
Is involved.

FIGS. 13 and 14 show the relationship between the filtration rate and the SS removal rate, and the relationship between the SV and the NO _x --N removal rate in the experiments conducted to understand the proper conditions. From these figures, the filtration speed is 100 m / day or less,
It can be seen that SV can be processed if it is 3 / Hr or less. Although the filtration rate and SV can be processed even if they are less than the lower limit values, the numerical values are limited because the size of the device becomes excessive.

When the simply treated water completed the above reaction and entered the upper aeration zone, the aerobic microorganisms in which the BOD components remaining in the denitrification in the non-aeration zone were immobilized on granular zeolite were supplied by aeration. Decomposes using dissolved oxygen.
There are no special conditions for the BOD decomposition in the aeration zone, the dissolved oxygen at the outlet of the non-aeration zone is 1 mg / L or more, the filtration rate is 100 m / day or less, and the SV is 3 /.
If it is at most Hr, the process proceeds normally. In this way, the simplified treated water that has passed through the granular zeolite layer flows out from the upper portion of the advanced treatment device 8 as the advanced treated water as shown in FIG. 3, and once stored in the advanced treated water storage tank 9, it is necessary. It is sterilized according to the regulations and discharged into rivers.

When the treatment is continued in this way, the water resistance of the granular zeolite layer increases. When the water flow resistance reaches a certain value, air washing and water washing of the granular zeolite layer are carried out. The procedure is water draining → water filling → air backwashing → simultaneous water / air backwashing → water backwashing. In particular, the operation of draining water is important, and a draining speed of 2 m / min or more is required in the granular zeolite layer. This drainage removes coagulated sludge accumulated in the lower space of the advanced treatment equipment and peels off coagulated sludge that adheres in high concentration near the entrance of the non-aeration zone, and discharges it if the water removal rate is low. Is not achieved.

FIG. 15 shows the relationship between the water removal rate and the coagulated sludge discharge rate, but in order to discharge the coagulated sludge by 80% or more, a water removal rate of 2 m / min or more is required. Other conditions for air cleaning and water cleaning are the same as those for general sand filtration equipment, but if it is difficult to take the time for the main cleaning due to the rainfall interval, etc. If it is inserted between the main cleaning and the main cleaning, a recovery rate of 70 to 85% of the recovery rate of water resistance due to the main cleaning can be obtained. Figure 1
6 shows this state.

Although the simple treated water that has been retained in the retaining basin 7 through the above process is subjected to advanced treatment, the advanced treatment device 8
In the aeration zone in, the anthracite, the sintered aggregate and the like can be used in place of the granular zeolite. This is because the adsorption of NH ₄ —N is not required in the aeration zone, and a cheaper carrier than granular zeolite can be used.

On the other hand, granular zeolite,
For advanced treatment equipment that is filled with manganese dioxide in the upper part, an air-cleaning diffuser in the lower part of the granular zeolite packed bed, and an ozone supply device in the lower part of the manganese dioxide layer, except for the manganese dioxide layer part It is similar to the law. The height of the total packed bed is 2 to 4 m, and the ratio of the height of the granular zeolite and the height of manganese dioxide is about 1: 1. The manganese dioxide used has a granular shape of 20 to 70 mm or a comb shape, and a partition such as punching metal is required at the boundary with the granular zeolite. This is because the specific gravity of manganese dioxide is larger than that of the granular zeolite, so that the manganese dioxide is mixed into the granular zeolite by backwashing.

The principle of treatment is the same as the treatment up to the granular zeolite in the non-aeration zone in the above method up to the treatment with the granular zeolite, and only the manganese dioxide treatment is different from the above. Due to the action of manganese dioxide and ozone, the BOD derived from road drainage and the added hydrogen donor that had become excessive during the previous denitrification were decomposed in the easily treated water that entered the manganese dioxide layer. The persistent COD is also decomposed. Manganese dioxide after decomposing the organic matter changes to manganese oxide, but due to the action of coexisting ozone, it returns to manganese dioxide again. The ozone supplied to the manganese dioxide layer should be 1.5 to 2 times the COD of the simply treated water.

FIG. 17 shows the relationship between the ozone addition rate and the COD removal rate, but 1.5 to 2 times the COD is necessary. In addition, processing is possible even if it exceeds 2 times,
It is uneconomical because the COD removal rate does not improve relative to the addition rate. A chlorine-based oxidant and a permanganate salt can be used instead of ozone, but in using them, it is necessary to consider generation of chlorine compounds and manganese oxide.

The simple treated water treated in this way flows out from the upper part of the advanced treatment equipment 8 and is discharged to a river or the like as in the advanced treatment method described above. Further, the method of air washing and water washing when the water resistance of the granular zeolite layer and the manganese dioxide layer increases is the same as the advanced treatment described above.

The outline of the simple treatment method and the advanced treatment method of the present invention has been described above. The wash water discharged from each process is discharged to the sewer as it is, or concentrated and dehydrated for disposal.

[0034]

[Example] On a local highway, from the start of rainfall until the accumulated rainfall reaches 2 mm, a simple treatment with a flotation filter is performed near the gutter, and the simple treated water is homogenized and then filled with granular zeolite. Table 2 shows the result of advanced treatment using the column.

[0035]

[Table 2]

As can be seen from Table 2, the water quality of road drainage from the beginning of heavy pollution to the accumulated rainfall of 2 mm can be greatly improved by the simple treatment by the flotation filter, and further advanced treatment is required. The water is treated so that there is no problem even if it is released into public water bodies such as rivers.

[0037]

[Effects of the Invention] 1. If a simple process using a flotation filter is performed at the lower part of the road, the head difference with the road can be used, and therefore the process can be performed without requiring power. 2. In the area where the combined sewer system is installed, the amount of rainwater that flows into the sewer system can be reduced, so the frequency of untreated sewage overflow from the rainwater discharge can be reduced and pollution of public water areas can be prevented. 3. It is possible to reduce the pollution load of public water areas commensurate with simple treatment and advanced treatment in the sewage laying area where the drainage of roads is discharged to rivers and in the undeveloped sewer area.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an embodiment of the invention of claim 1.

FIG. 2 is a flow sheet showing another embodiment of the invention of claim 1;

FIG. 3 is a flow sheet showing an embodiment of the invention of claim 2;

FIG. 4 is a graph showing the relationship between average rainfall intensity and discharge amount.

FIG. 5 is a graph of a pressure loss recovery rate of a floating filter medium.

FIG. 6 is a graph showing the relationship between the particle size of the floating filter medium and the pressure loss per unit SS detention amount.

FIG. 7 is a graph showing the relationship between filtration rate and SS removal rate.

FIG. 8 is a graph showing the relationship between the SS retention amount and the SS removal rate of a filter medium.

FIG. 9 is a graph showing the relationship between cumulative rainfall and road drainage SS.

FIG. 10 is a graph showing the relationship between cumulative rainfall and SS processability.

FIG. 11 is a layout diagram showing an application example to an elevated road.

FIG. 12 is a graph of supernatant water SS.

FIG. 13 is a graph showing the relationship between filtration rate and SS removal rate.

FIG. 14 is a graph showing the relationship between SV and NO _x —N removal rate.

FIG. 15 is a graph showing the relationship between the water removal rate and the coagulated sludge discharge rate.

FIG. 16 is a graph showing the recoverability of water resistance.

FIG. 17 is a graph showing the relationship between the ozone addition rate and the COD removal rate.

[Explanation of symbols]

1 gutter, 2 screen, 3 flotation filter device, 4 flotation filter material, 5 sand filtration device, 6 simple treatment water tank, 7 holding tank, 8 advanced treatment device, 9 advanced treatment water tank, 10 air diffuser, 11 aeration Air diffuser

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/72 C02F 1/78 4D041 1/78 3/06 4D050 3/06 3/10 A 4D059 3/10 3/34 101D 3/34 101 9/00 501G 9/00 501 501H 502D 502 502H 502R 503C 503 504A 504 504E 11/12 Z 11/12 B01D 23/16 (72) Inventor Hideki Takeuchi Mizuho Ward, Nagoya City, Aichi Prefecture Sudamachi No. 56 No. 56 Nikko Inshiko Co., Ltd. F-term (reference) 2D063 DB05 4D003 AA01 BA02 CA10 EA01 EA22 EA23 FA10 4D015 BA19 BA23 BB05 CA20 DA02 DA12 EA02 FA16 FA26 4D024 AA10 AB01 AB01 AB02 BA13 BA01 BA05 BA07 BB01 BC01 CA01 CA01 DB16 4D040 BB07 BB42 BB63 BB82 BB93 4D041 BA01 BA21 BB04 BB07 BC01 BC02 BD16 CA04 CA07 CA08 4D050 AA20 AB07 AB 11 BB02 BB11 BD06 CA15 CA16 CA17 4D059 AA30 BE00 CA28

Claims (8)

[Claims] 1. A method for removing and treating road drainage by providing a gutter on the side surface of the road, by simply treating the road drainage introduced from the gutter and discharging the treated water to a public water area such as a river to generate sludge. Is a method of treating road drainage, which is characterized by draining it into a sewer pipe or disposing it after dehydration treatment. 2. A method for treating and removing road drainage by providing a gutter on the side surface of the road, wherein a drainage pond is provided at the lower part of the road to easily treat the road drainage introduced from the gutter, and the simplified treated water is supplied to the drainage pond. In addition to retaining water, the simple treated water is subjected to advanced treatment before being discharged into public water areas such as rivers, and sludge generated by simple treatment and advanced treatment is discharged to a sewer pipe or disposed of after dehydration treatment. Road wastewater treatment method. 3. The road drainage, which has an average rainfall intensity of 0.5 mm / Hr or more on the entire target road, and has an average of 2 mm from the beginning of rainfall, is subjected to simple treatment and advanced treatment,
The road drainage of the portion where the accumulated rainfall exceeds 2 mm on average is discharged only by simple treatment, and the road drainage of the portion where the accumulated rainfall exceeds 5 mm on average is discharged without treatment. The method for treating road drainage according to 1 or 2. 4. The volume of a water reservoir provided at the bottom of the road is such that the rainfall intensity on the entire target road is 0.5 mm / Hr or more on average, and the accumulated rainfall corresponds to 2 mm on average. The method for treating road drainage according to claim 2. 5. A simple method for treating road drainage is to pass a treatment tank filled with a floating filter medium after passing through a 2 mm screen and to pass water through an upward flow method at a filtration speed of 250 m / day or less, and The method for treating road drainage according to claim 1 or 2, wherein when the SS detention amount reaches 5 kg / m ³ , the filter medium is washed with water at a downward washing rate of 1 to 5 m / min. 6. A simple method for treating road drainage is as follows: after passing through a 2 mm screen, a treatment tank filled with a floating filter medium is passed through an upward flow method at a filtration speed of 250 m / day or less, and When the SS detention amount reached 5 kg / m ³ , the filter medium was washed with water at a downward washing speed of 1 to 5 m / min, and the outflow water was further filtered through a treatment tank filled with filter sand at a filtration speed of 50 to 2
2. The water is passed through the downflow method or the upflow method at 00 m / day, and the air washing and the water washing are performed when the water passage resistance of the filter layer reaches a certain value.
Alternatively, the method for treating road drainage described in 2. 7. An advanced treatment method for road drainage is a treatment tank in which a coagulant and a hydrogen donor are added to simple treated water in advance, and then granular zeolite is filled and the upper portion can be aerated with a filtration rate of 50 to 50.
100 m / day, SV2-3 / Hr, water is passed by an upflow method, and when the water resistance of the filter layer reaches a certain value, air washing and water washing are performed. Item 2. The method for treating road drainage according to item 2. 8. An advanced treatment method for road drainage is a treatment tank in which a coagulant and a hydrogen donor are added to simple treated water in advance, manganese dioxide is charged in the upper part and granular zeolite in the lower part, and the upper part is aerated with ozone. Filtration speed 50-100m
/ Day, SV2 to 3 / Hr, water is passed in an upward flow system, and air washing and water washing are performed when the water passage resistance of the filter layer reaches a certain value. 2. The method for treating road drainage described in 2.