JP6789537B2 - Watering filter cleaning method - Google Patents

Description

The present invention relates to a watering filter cleaning method .

As a method for treating wastewater such as sewage and factory wastewater, a biological wastewater treatment method for treating wastewater by microorganisms is widely used. Known biological wastewater treatment methods include an activated sludge method, a sprinkling filter method, and a circulating nitrification denitrification method. The activated sludge method is a method of inflowing wastewater into activated sludge containing aerobic microorganisms to remove organic substances in the wastewater, and is a typical biological wastewater treatment method in Japan. The activated sludge method requires aeration to send air into the wastewater in the activated sludge in order to maintain the activity of aerobic microorganisms. The sprinkler filter method is a process in which wastewater is sprinkled from the upper side of the filter bed and the drainage drips on the surface of the filter medium by using a sprinkler filter device having a filter bed formed of a large number of crushed stone or plastic filter media. , Organic substances in wastewater are removed by the action of a film of aerobic microorganisms that grows on the surface of the filter medium. Since the supply of oxygen to the membrane of aerobic microorganisms depends on the diffusion movement or dissolution of oxygen in the air existing in the gaps of a large number of filter media, aeration becomes unnecessary. The circulating nitrification denitrification method involves removing organic substances, a nitrification step in which ammonia in wastewater is oxidized to nitrate ions by aerobic microorganisms, and a denitrification step in which nitrate ions are reduced to nitrogen molecules by anaerobic microorganisms. , It removes nitrogen, which is one of the causative substances of eutrophication.

The activated sludge method requires a large amount of air for aeration and therefore consumes a large amount of electric energy. Since the circulating nitrification denitrification method requires aeration in the nitrification step, it generally requires a larger amount of air than is required by the activated sludge method, and therefore consumes a larger amount of electric power energy. On the other hand, the sprinkling filter method does not require aeration, so that the power energy consumed can be reduced.

Since the watering filter method is operated with air entering and exiting the gaps between many filter media, the hygiene pests (so-called filter bed flies) easily enter the gaps between the filter media and use the filter media as a spawning bed. By using it, it tends to occur in large quantities. Therefore, it is necessary to take measures to prevent the flies from becoming a major obstacle in operating the introduced sprinkler filter. For example, Patent Document 1 discloses a sprinkling filter device using a cloth having hydrophilicity and water absorption as a filter medium. Here, it is stated that flies do not occur because the layer of aerobic microorganisms formed on the fabric is covered with a water film. Further, for example, in Patent Document 2, in order to prevent the occurrence of flies, a washing water storage mechanism that stores washing water in the device and floods (submerges) the filter medium, and a washing water storage mechanism that floods the filter medium and then cleans from the sprinkling filter bed device. A sprinkler filter device including a drainage mechanism for discharging water and a cleaning means having the same is disclosed.

Japanese Unexamined Patent Publication No. 2001-121181 JP 2015-0336666

However, since the sprinkling filter device disclosed in Patent Document 1 does not have a means for cleaning the filter medium, it is a problem whether or not the generation of flies can be effectively suppressed after continued use, and the filter medium can be used as a filter medium. It is considered that the service life of the fabric is not long. Further, in the sprinkling filter device disclosed in Patent Document 2, depending on the place where it was laid, it is often difficult to remove eggs and the like only by flooding with washing water and discharging the washing water. it is conceivable that.

The present invention has been made in view of the above reasons, and an object of the present invention is to provide a watering filter cleaning method capable of effectively suppressing the generation of flies.

In order to achieve the above object, the watering filter device cleaning method according to claim 1 accommodates a watering filter formed of a large number of filter media and performs wastewater treatment at the time of wastewater treatment to remove oxygen-free treated water. The main body of the sprinkler filter device to be discharged to the floor device, the cleaning equipment for flooding the sprinkler filter bed with cleaning water at the time of cleaning, and the cleaning of the sprinkler filter bed flooded with the wash water by air explosion. It is a method of cleaning a sprinkling filter device that periodically cleans a sprinkling filter equipped with an air aeration facility for cleaning. At the time of cleaning, the washing water is injected by the cleaning flooding facility to fill the sprinkling filter. After watering, the sprinkler filter bed is air-ventilated by the cleaning air aeration facility to promote the peeling of the larvae and eggs of the flies attached to the filter medium, and then a part of the 蠅from the upper part of the sprinkler filter bed. The washing water containing the above-mentioned washing water is discharged to the settling device, and then the washing water containing the rest of the 蠅 is discharged from the lower part of the sprinkler filter bed to the settling device .

The method for cleaning the sprinkler filter according to claim 2 is to fill the main body of the sprinkler filter device, which accommodates the sprinkler filter formed of a large number of filter media and performs wastewater treatment, and the sprinkler filter with washing water at the time of cleaning. A sprinkler filter device cleaning that periodically cleans a sprinkler filter device including a flushing facility for washing with water and an air exposure facility for cleaning that air-explodes the sprinkling filter flooded with the washing water. In this method, the washing water is injected by the cleaning equipment to flood the sprinkling filter, and then the watering filter is air-exposed by the cleaning air aeration equipment to adhere to the filter medium. The amount of the larvae and eggs of the sprinkled washer is promoted, and then the amount is more than the amount accumulated from the upper surface of the watering filter bed to a depth of 50 mm and less than the amount accumulated from the upper surface of the watering filter bed to a depth of 400 mm. The amount of the washing water is discharged from the upper part of the sprinkling filter, and then the washing water is discharged from the lower part of the sprinkling filter .

The sprinkling filter device cleaning method according to claim 3 is the water sprinkling filter device cleaning method according to claim 1 or 2 , wherein tap water, well water, or wastewater treated water is used as the washing water used for the flooding. It is characterized by.

The method for cleaning the sprinkler filter according to claim 4 is to fill the main body of the sprinkler filter device, which accommodates the sprinkler filter formed of a large number of filter media and performs wastewater treatment, and the sprinkler filter with washing water at the time of cleaning. A sprinkler filter device cleaning that periodically cleans a sprinkler filter device including a flushing facility for washing with water and an air exposure facility for cleaning that air-explodes the sprinkling filter flooded with the washing water. According to the method, the filter medium is made of a cylindrical plastic having a diameter of 10 to 30 mm and a length of 10 to 30 mm, and the washing water is injected by the washing equipment to flood the sprinkling filter bed. After that, the air volume is set to 0.6 to 1.0 m ³ / m ² · min and the air exposure time is set to 1 to 5 min by the cleaning air aeration facility , and the sprinkler filter bed is air- exposed to the filter medium. It is characterized in that it promotes the detachment of larvae and eggs of the flies attached to the shavings, and then drains the washing water .

The watering filter cleaning method according to claim 5 is the watering filter cleaning method according to any one of claims 1 to 4 , wherein the frequency of periodically cleaning the watering filter is 3 days. It is characterized in that it is performed once or more.

According to the watering filter cleaning method of the present invention, it is possible to effectively suppress the generation of flies.

It is the schematic of the circulation type nitrification denitrification system including the sprinkling filter device which concerns on embodiment of this invention. The above-mentioned sprinkler filter device is shown, in which (a) is a front sectional view and (b) is a plan view. It is an enlarged external view which shows the example of the filter medium of the sprinkler filter of the same above, (a) is a front view, (b) is a side view. The anoxic filter used in the circulation type nitrification denitrification system together with the watering filter of the above is shown, in which (a) is a plan view and (b) is a cross-sectional view on a cut surface shown by AA. Is. It is a graph which shows the population distribution of the larva of the side part of the sprinkling filter in the experiment of the sprinkling filter of the same above, and is about the sprinkling filter which was washed. It is a graph which shows the population distribution of the larva of the side part of the sprinkling filter in the experiment of the sprinkling filter of the same above, and is about the sprinkling filter which did not wash. It is a graph which shows the number of larvae, pupae, and adults about the flies contained in the washing water discharged from the watering filter device in the experiment of the watering filter device as above, and is for all the washing water. It is a graph showing the number of larvae, pupae, and adults for the flies contained in the washing water discharged from the watering filter in the same experiment of the watering filter, and is only for the washing water discharged from the bottom. is there. It is a graph which shows the individual size of the larva by month in the sprinkling filter in the experiment of the sprinkling filter of the same above, and shows the sprinkling filter which was washed and the sprinkling filter which was not washed. .. It is a graph which shows the time-dependent change of the nitrogen concentration of each state in the wastewater flowing into the circulation type nitrification denitrification system in the experiment of the sprinkler filter of the same above. It is a graph which shows the time-dependent change of the nitrogen concentration of each state in treated water in the experiment of the sprinkling filter device of the same above, and is about the sprinkling filter device which performed washing. It is a graph which shows the time-dependent change of the nitrogen concentration of each state in treated water in the experiment of the sprinkling filter device of the same above, and is about the sprinkling filter device which did not wash. It is a graph showing the time course of COD (Chemical Oxygen Demand) in the treated water in the experiment of the sprinkler filter device as above, and shows the sprinkler filter device that was washed and the sprinkler filter device that was not washed. ing. It is a graph which shows the time-dependent change of SS (suspended solids amount) in treated water in the experiment of the sprinkling filter device of the same above, and shows the sprinkling filter device which was washed and the sprinkling filter device which was not washed. ..

Hereinafter, modes for carrying out the present invention will be described. As shown in FIG. 1, the watering filter device 1 according to the embodiment of the present invention is a device that constitutes a part of the circulation type nitrification denitrification system 2. The circulation type nitrification denitrification system 2 is a system that realizes the above-mentioned circulation type nitrification denitrification method. In the circulation type nitrification denitrification system 2, the sprinkler filter device 1 performs a nitrification step of oxidizing ammonia in the waste water W to nitrate ions by aerobic microorganisms. The watering filter device 1 also contributes to the removal of organic matter in the waste water W by aerobic microorganisms.

As shown in FIG. 1, the sprinkling filter device 1 includes a sprinkling filter main body 3, a cleaning flooding facility 4, and a cleaning air aeration facility 5.

As shown in FIGS. 2A and 2B, the watering filter main body 3 has a watering filter 32 formed by a large number of filter media (carriers) 32a inside the tubular watering filter outer cylinder 31. To accommodate. In the watering filter bed 32, the wastewater W is sprinkled from above, and the wastewater W can slowly flow downward inside to perform the wastewater treatment. The filter medium 32a captures sludge (deposited sludge), and aerobic microorganisms capable of oxidizing ammonia in the waste water W to nitrate ions grow on the surface of the filter medium 32a. The upper surface and the lower surface of the watering filter bed 32 are exposed to the outside air to supply air, and oxygen in the air diffuses and moves through the gaps of a large number of filter media 32a. Further, oxygen in the air diffuses and moves even if it is dissolved in the waste water W supplied from the upper surface of the sprinkler bed 32. In this way, oxygen is supplied to the membrane of aerobic microorganisms. In FIG. 2B, the washing water injection pipe 41, the air injection pipe 51, and the upper discharge pipe 44, which will be described later, are not shown.

The filter medium 32a is a molded product made of plastic (for example, made of high-density polyethylene). The plastic filter medium 32a has a smaller specific gravity than the crushed stone filter medium. As a result, the filter medium 32a can be easily moved by air aeration during washing, which will be described later, and can promote the peeling of fly larvae and eggs attached to the filter medium 32a. The specific gravity of the filter medium 32a can be 0.9 to 1.1. Further, the filter medium 32a can have various shapes, and for example, as shown in FIG. 3, it can be a cylindrical one.

The watering filter floor outer cylinder 31 can be attached with a thin plate-shaped support 33 having a large number of meshes so as to close the bottom of the hollow portion. The mesh-like support 33 supports a large number of filter media 32a of the watering filter bed 32 housed in the watering filter bed outer cylinder 31. Therefore, the mesh size of the support 33 is smaller than that of the filter medium 32a.

Further, the watering filter floor outer cylinder 31 may be provided with a pipe attachment 34 for attaching the lower discharge pipe 35, the washing water injection pipe 41, and the air injection pipe 51, which will be described later, under the watering filter floor outer cylinder 31. it can. The pipe fitting 34 has an internal space, and the hollow portions of the lower discharge pipe 35, the washing water injection pipe 41, and the air injection pipe 51, which will be described later, communicate with the internal space. The tube attachment 34 may have a substantially conical shape as shown. Further, the sprinkler filter floor outer cylinder 31 and the pipe fixture 34 have flanges 31a and 34a, respectively, and are fixed to each other by fixtures (bolts, nuts, etc.) at the flanges 31a and 34a to form the sprinkler filter bed 32. The internal space of the pipe fitting 34 can be located directly below. Further, the support 33 can be attached by sandwiching it between the sprinkler filter floor outer cylinder 31 and the pipe attachment 34.

The sprinkler filter main body 3 has a lower discharge pipe 35 through which the treated water P that has passed through the sprinkler filter 32 is discharged during wastewater treatment. The lower discharge pipe 35 is provided with a three-way cock 36 so that the treated water P is discharged to the oxygen-free filter device 7 described later at the time of wastewater treatment, and the lower discharge pipe 35 is closed at the time of cleaning the sprinkling filter device 1. The watering filter bed 32 can be flooded, or the washing water C can be discharged to the settling device 6 described later (see FIG. 1).

The cleaning flooding facility 4 is a facility for flooding the sprinkling filter 32 at the time of cleaning the sprinkling filter device 1. The washing water inundation facility 4 has a washing water injection pipe 41 capable of injecting washing water C into the watering filter bed 32 from below. Specifically, the wash water injection pipe 41 can be attached to the pipe fitting 34 as described above. The wash water injection pipe 41 is usually provided with a cock 42 capable of arbitrarily opening and closing the wash water injection pipe 41, and a pump 43 is connected so as to discharge the wash water C upward. Further, as will be described later, when the washing water C is also discharged from the upper part of the sprinkling filter bed 32 after flooding, the upper discharge pipe 44 is provided.

The cleaning air aeration facility 5 is a facility that explodes the sprinkler filter 32 with air when cleaning the sprinkler filter device 1. The cleaning air aeration facility 5 has an air injection pipe 51 capable of injecting air A into the sprinkler bed 32 from below. Specifically, the air injection pipe 51 can be attached to the pipe fitting 34 as described above. The air injection pipe 51 is usually provided with a cock 52 that can be opened and closed arbitrarily, and an air pump 53 is connected so as to discharge air upward.

The circulating nitrification denitrification system 2 further includes the above-mentioned precipitation device 6 and anoxic filter bed device 7. The settling device 6 and the oxygen-free filter bed device 7 may have conventional functions and configurations, and will not be described in detail, but the basic functions and configurations are as follows.

In the settling device 6, the raw wastewater W before the treatment flows in, and the large solid matter S in the wastewater W is settled and separated. The drainage W from which the solid matter S has been separated and removed is sent to the oxygen-free filter device 7 by the pump 6A. The solid matter S is discharged by a predetermined mechanism.

The anoxic filter bed device 7 performs a denitrification step of reducing nitrate ions in the waste water W to nitrogen molecules by anaerobic denitrifying microorganisms. Further, the oxygen-free filter device 7 can also remove organic substances in the waste water W by anaerobic microorganisms. As shown in FIG. 4, the anaerobic filter device 7 is provided inside the anaerobic filter tank 71, in a filter bed 72 formed of a filter medium (carrier) overgrown with anaerobic microorganisms, and in the filter bed 72. It has a plurality of partition plates 73 and the like. Further, the oxygen-free filter bed device 7 has a drainage inflow pipe 74, a drainage outflow pipe 75, and a treated water outflow pipe 76. Further, the oxygen-free filter device 7 has an isolation plate 77 that isolates the drainage W and the treated water P. The drainage W flowing from the drainage inflow pipe 74 bypasses up and down between the plurality of partition plates 73, and organic substances are removed and denitrified through the filter bed 72. The drainage W that has passed through the filter bed 72 flows out from the drainage outflow pipe 75 and is sent to the sprinkler bed device 1 by the pump 7A (see FIG. 1). Further, the treated water P discharged from the sprinkler bed device 1 flows in from above, a part of the treated water P flows out from the treated water outflow pipe 76 as the final treated water P, and the rest is again filtered. It passes through the floor 72 and circulates to the watering filter bed device 1.

Next, the operation and operation of the watering filter device 1 will be described in detail.

First, the time of wastewater treatment will be described. At the time of wastewater treatment, in the sprinkler filter device 1, the cock 42 of the flush water injection pipe 41 of the sprinkler filter device 1 and the cleaning flooding facility 4 and the cock 52 of the air injection pipe 51 of the cleaning air aeration facility 5 are closed. ing. In the sprinkler filter device 1, drainage W is sprinkled from above the sprinkler filter 32, and in the process of the drainage W dripping on the surface of the filter medium 32a, the drainage W is drained by the action of a film of aerobic microorganisms growing on the surface of the filter medium 32a. The ammonia in W is oxidized to nitrate ions by aerobic microorganisms. In addition, organic substances in the wastewater W are also removed. The treated water P from the sprinkler filter device 1 is discharged to the oxygen-free filter device 7 through the lower discharge pipe 35 (and the three-way cock 36).

Next, cleaning of the sprinkler filter device 1 will be described. The water sprinkler bed device 1 is periodically washed by temporarily stopping the wastewater treatment.

At the time of cleaning the sprinkling filter device 1, the lower discharge pipe 35 (three-way cock 36) is closed, the washing water injection pipe 41 (cock 42) is opened, and the washing water C is injected to flood the sprinkling filter 32. After that, the air injection pipe 51 (cock 52) is opened to aerate the sprinkler bed 32 with air. By air aeration, the filter medium 32a is finely moved to promote the peeling of fly larvae and eggs attached to the filter medium 32a. At this time, in order to effectively promote the peeling of the fly larvae and eggs attached to the filter medium 32a, the plastic filter medium 32a is a cylindrical one having a diameter of 10 to 30 mm and a length of 10 to 30 mm, and is aerated with air. It is preferable that the air volume of the air is 0.6 to 1.0 m ³ / m ² · min and the air aeration time is set to 1 to 5 min. In addition, air aeration may be performed by the air injection pipe 51 while injecting the washing water C by the washing water injection pipe 41.

After the watering filter bed 32 is flooded and aerated with air, the washing water C accumulated in the watering filter bed 32 is discharged. In this case, it is possible to open the lower discharge pipe 35 (three-way cock 36) so that the washing water C is discharged to the settling device 6 and discharge the washing water C only from the lower part of the watering filter bed 32. Before discharging the washing water C from the lower part of the filter bed 32, it is preferable to discharge a part of the washing water C from the upper part of the sprinkling filter bed 32 through the upper discharge pipe 44. This is because, as shown in the experimental results described later, the abundance ratio of fly larvae is large in the upper part of the sprinkling filter 32, and therefore, the washing water C discharged from the upper part of the sprinkling filter 32 is discharged from the lower part. This is because it contains an extremely large amount of flies as compared with the washing water C. To discharge a part of the washing water C from the upper part of the sprinkling filter 32, open the washing water injection pipe 41, inject the washing water C, and push the washing water C accumulated in the sprinkling filter 32 upward. do it.

The amount of wash water C discharged from the upper part of the sprinkling filter 32 is preferably an amount equal to or more than the amount accumulated from the upper surface of the sprinkling filter 32 to a depth of 50 mm. This is based on the fact that the effect was confirmed by the experimental results described later in which the amount of washing water C accumulated from the upper surface of the sprinkling filter 32 to a depth of 50 mm is discharged from the upper part of the sprinkling filter 32. Further, the amount of wash water C discharged from the upper part of the sprinkling filter 32 is preferably an amount equal to or less than the amount accumulated from the upper surface of the sprinkling filter 32 to a depth of 400 mm. This is because, according to the experimental results described later, the fly larvae are concentrated in the upper part of the sprinkling filter 32, particularly in the section having a depth of 0 to 400 mm, and the washing water C discharged from the upper part of the sprinkling filter 32. It is based on the fact that too much is not economical.

As the wash water C used for flooding, tap water, well water, or wastewater treated water such as the one storing the treated water P can be used.

There are several types of flies, such as Psychoda albipunchata and Psychoda alternata of the Psychodidae family. Fly eggs laid on the sprinkler bed 32 hatch within 48 hours and become adults within 1-3 weeks. The grown and grown larvae are easily physically captured by the filter medium 32a, and the removal effect by washing is small. Therefore, it is assumed that the eggs and small larvae immediately after hatching will be removed, and the washing frequency is once every 3 days. The above is preferable.

As described above, the sprinkling filter device 1 can effectively suppress the generation of flies by periodically suspending the wastewater treatment and performing the above-mentioned cleaning.

By cleaning the watering filter bed 32, the accumulated sludge trapped in the filter medium 32a is also slightly removed. As a result, there is a concern that the amount of aerobic microorganisms on the surface of the filter medium 32a may decrease, which may adversely affect the water treatment capacity, which is the original function of the watering filter bed device 1, but the experimental results described later (FIG. As shown in 8A to FIG. 10), the water treatment capacity does not decrease. On the contrary, cleaning the watering filter bed 32 prevents exfoliation of accumulated sludge and its outflow during wastewater treatment, and maintains an aerobic microbial film on the surface of the filter medium 32a in an appropriate state. Water treatment capacity can be maintained.

Further, the sprinkling filter device 1 is a device that constitutes a part of the circulation type nitrification denitrification system 2 in this way, is a device that constitutes a part of another system, or is a sprinkling device described above as a single unit. It can be used as a device that realizes the filter bed method. In this case, of course, various aerobic microorganisms are possible.

Next, the experiment of the sprinkling filter device 1 and the cleaning method thereof performed by the inventor of the present application will be described below. In this experiment, the circulating nitrification denitrification system 2 shown in FIG. 1 was used. The sprinkling filter outer cylinder 31 of the sprinkling filter device 1 has a cylindrical shape made of transparent acrylic, and has a height of 1000 mm and an inner diameter of 80 mm.

As the filter medium 32a, a cylindrical high-density polyethylene molded product (specific gravity 0.98) (Lamer tube LT-15 manufactured by Dainippon Plastics Co., Ltd.) having a diameter of 15 mm and a length of 15 mm was used. About 540 g (bulk volume 4.5 L, filling height about 900 mm) of these filter media 32a was filled in the sprinkling filter bed outer cylinder 31 to form the sprinkling filter bed 32.

A mesh-like support 33 is attached to the bottom of the watering filter floor outer cylinder 31. Further, the support 33 is provided with a lower discharge pipe 35, a washing water injection pipe 41, and an air injection pipe 51. A three-way cock 36 is provided in the lower discharge pipe 35, and the treated water P is discharged to the anoxic filter bed device 7 at the time of wastewater treatment, and the washing water C is discharged to the settling device 6 at the time of cleaning the sprinkling filter bed device 1. The washing water injection pipe 41 is provided with a cock 42, and the air injection pipe 51 is provided with a cock 52 so that it can be opened and closed arbitrarily. Further, an air pump 53 having a discharge rate of 3 L / min is connected to the air injection pipe 51.

The oxygen-free filter bed device 7 is a tank type having a width of 70 mm, a height of 125 mm, and a depth of 320 mm, and the tank is filled with a string-shaped contact material (Cleocord KC-30 manufactured by Dainippon Plastics Co., Ltd.) by 180 cm.

Two circulating nitrification denitrification systems 2 (circulation nitrification denitrification systems 2A and 2B) were prepared for the experiment, and the experiment was conducted as follows.

From the start date of the experiment (April 25, 2015) to May 31, 2015, only wastewater treatment was performed in the circulating nitrification denitrification systems 2A and 2B, and the watering filter device 1 was not washed. .. Since the occurrence of flies was confirmed on June 1, 2015, the circulation type nitrification denitrification system 2A has been subjected to the following washings at a constant frequency since then. In the circulation type nitrification denitrification system 2B, even after June 1, 2015, cleaning was not performed and only wastewater treatment was continued.

During the period from June 1st to July 16th, 2015 (period 1), in the circulation type nitrification denitrification system 2A, the wastewater treatment is temporarily stopped once every three days. 1 was washed. That is, the lower discharge pipe 35 was closed, the washing water injection pipe 41 was opened, and the washing water C was supplied to the height of the watering filter bed 32 up to 990 mm, and the watering filter bed 32 was flooded. Next, the washing water injection pipe 41 was closed, the air injection pipe 51 was opened, and air aeration was performed for 3 minutes at an air flow rate of 3 L / min (aeration air volume 0.6 m ³ / m ² min). After the completion of aeration, the air injection pipe 51 was closed, the lower discharge pipe 35 was opened, and the washing water C was discharged from the lower part of the sprinkler filter bed 32.

During the period from July 17th to August 22nd, 2015 (period 2), in the circulating nitrification denitrification system 2A, the wastewater treatment is temporarily stopped once every three days. Cleaning was performed. That is, the lower discharge pipe 35 was closed, the washing water injection pipe 41 was opened, and the washing water C was supplied to the height of the watering filter bed 32 up to 990 mm, and the watering filter bed 32 was flooded. Next, the washing water injection pipe 41 was closed, the air injection pipe 51 was opened, and air aeration was performed for 3 minutes at an air flow rate of 3 L / min (aeration air volume 0.6 m ³ / m ² min). After the aeration is completed, the air injection pipe 51 is closed, and 200 mL (5% of the total washing water) (the amount accumulated from the upper surface of the sprinkling filter 32 to a depth of 50 mm) is washed from the upper part of the sprinkling filter 32 through the upper discharge pipe 44. After discharging the water C, the lower discharge pipe 35 was opened to discharge the remaining washing water C from the lower part of the sprinkling filter bed 32.

During the experiment period, the number of fly larvae, pupae, and adults in the discharged wash water C was counted, and the side photographs of the watering filter bed 32 were taken regularly to count the number of fly larvae recorded in the photographs. did.

The experimental results are as follows. Two types of flies, Psychoda albipunktata and Psychoda alternata, were observed, but both are shown together in the figures described below showing the experimental results.

5A and 5B show the distribution of fly larvae on the side surface of the watering filter bed 32 during the above periods 1 and 2 (the number of individuals observed in a side area of 3.85 × 10 ^-3 m ² ). .. The horizontal axis is the month and day, and the vertical axis is a bar graph. Section a from the top to 200 mm, section b from 200 to 400 mm, section c from 400 to 600 mm, section d from 600 to 800 mm, section e from 800 to 1000 mm, The number of larvae in. FIG. 5A shows the circulation type nitrification denitrification system 2A, and FIG. 5B shows the circulation type nitrification denitrification system 2B.

From FIGS. 5A and 5B, it can be seen that in period 1, the number of fly larvae in the circulating nitrification denitrification system 2A is significantly reduced as compared with the circulation nitrification denitrification system 2B (more details). 66.0% decrease). This is a result of washing once every three days and removing the larvae or eggs with the washing water C discharged from the lower part of the watering filter bed 32. Further, in the circulation type nitrification denitrification system 2A, the amount of accumulated sludge trapped in the filter medium 32a was reduced to the extent that it could be visually recognized, and the reduction of sludge that feeds the larvae also contributed to the reduction of larvae. It is considered to be.

Further, from FIGS. 5A and 5B, it can be seen that in the period 1, the larvae are concentrated in the upper part of the watering filter 32, particularly in the section of 0 to 400 mm in both the circulating nitrification denitrification systems 2A and 2B. Further, in the circulation type nitrification denitrification system 2A, almost no larvae were confirmed in the section of 600 to 1000 mm from the upper part of the watering filter bed 32. Adult flies invade from the upper part of the watering filter 32 and lay eggs, and by washing the watering filter 32, eggs and larvae in the lower part of the watering filter 32 are preferentially contained in the washing water C and removed. That is considered to be a factor.

Further, from FIGS. 5A and 5B, in the period 2, the number of fly larvae in the circulating nitrification denitrification system 2A was reduced to 15.5% as compared with the circulation nitrification denitrification system 2B. It was washed once every three days during period 2 and drained from the top of the sprinkler bed 32 before the larvae or eggs were removed by the wash water C drained from the bottom of the sprinkler bed 32. This is the result of removing the larvae or eggs with the washing water C, and the effect of using the washing water C discharged from the lower part and the upper part of the watering filter 32 in combination was confirmed.

Next, FIGS. 6A and 6B show the numbers of larvae, pupae, and adults of the flies contained in the washing water C discharged from the sprinkler bed device 1 in the circulating nitrification denitrification system 2A. The horizontal axis is the month and day, the vertical axis on the right side is the number of larvae shown in the line graph f, and the vertical axis on the left side is the number of pupae (part of code g) and adults (part of code h) shown in the bar graph. FIG. 6A shows the entire washing water C (the total of the washing water C discharged from the lower part and the washing water C discharged from the upper part), and FIG. 6B shows only the washing water C discharged from the lower part. is there. No adults were observed in the washing water C discharged from the lower part. In FIG. 6A, the data in period 1 is the same as in FIG. 6B, so it is omitted.

From FIGS. 6A and 6B, the number of pupae (larvae, pupae, adults) contained in the washing water C discharged from the upper part of the watering filter 1 is extremely large as compared with the washing water C discharged from the lower part. Therefore, it can be seen that the effect of removing the pupae by discharging the washing water C from the upper part is extremely large as compared with the discharging of the washing water C from the lower part. Specifically, the number of flies contained in the washing water C discharged from the upper part reached 860 ± 176 times the number of flies contained in the washing water C discharged from the lower part. From FIGS. 6A and 6B, the number of flies contained in the washing water C decreased from around August 1st, two weeks after the beginning of the period 2, due to the washing of the sprinkler filter 1. It is considered that this is because the eggs were effectively removed and the number of eggs laid was suppressed by the decrease of adults due to the washing of the sprinkler bed device 1.

In addition, Table 1 below shows the numbers (mean and standard deviation) of larvae, pupae, and adults contained in each 1 L of the wash water C discharged from the upper part and the wash water C discharged from the lower part in the period 2.

Next, FIG. 7 shows the individual size of the larvae by month in the watering filter device 1. In each month, the left side is for the circulating nitrification denitrification system 2A and the right side is for the circulating nitrification denitrification system 2B. In June, when the washing of the watering filter device 1 was started, no significant difference was observed in the individual size of the larvae between the circulating nitrification denitrification systems 2A and 2B. Since July, the individual size of the circulating nitrification denitrification system 2B has not changed, but the average individual size of the circulating nitrification denitrification system 2A has increased 1.95 times. This is because larvae with a large individual size are easily physically captured by the filter medium 32a in the watering filter bed 32, so that the larvae with a small individual size were preferentially removed by washing in the circulating nitrification denitrification system 2A. It is considered that this is the result of.

From the experimental results shown in FIGS. 5A to 7 above, it can be seen that the generation of flies can be effectively suppressed by performing the above-mentioned cleaning of the watering filter device 1.

Next, the experimental results on the effect of cleaning the watering filter 1 on the water treatment capacity will be described. As an index of water treatment capacity, changes over time in each state nitrogen concentration, COD (chemical oxygen demand), and SS (suspended solids amount) in the treated water P were investigated.

8A-8C show the time course of nitrogen concentration in each state. FIG. 8A shows the time course of the concentration of nitrogen in each state in the wastewater W flowing into the circulating nitrification denitrification system 2A or 2B, and FIG. 8B shows the nitrogen in each state in the treated water P in the circulating nitrification denitrification system 2A. The time course of the concentration is shown, and FIG. 8C shows the time course of the nitrogen concentration of each state in the treated water P in the circulating nitrification denitrification system 2B. The part of the symbol l in FIGS. 8B and 8C indicates the concentration of nitrite ion. The part of the symbol m in FIGS. 8B and 8C indicates the concentration of nitrate ion. The part with reference numeral i in FIG. 8A and the part with reference numeral n in FIGS. 8B and 8C indicate the concentration of ammonia ions. The portion of reference numeral j in FIG. 8A, the portion of reference numeral o in FIGS. 8B and 8C shows other aspects. Further, the curves k in FIGS. 8B and 8C show the nitrogen concentration in the treated water P (the nitrogen concentration in each state) from the nitrogen concentration (total of the nitrogen concentration in each state) of the waste water W flowing into the circulating nitrification denitrification system 2A or 2B. It is the nitrogen removal efficiency obtained by subtracting).

From FIGS. 8A to 8C, no deterioration in water treatment performance was observed in the circulating nitrification denitrification system 2A. Therefore, from the viewpoint of the concentration of nitrogen in each state, it can be seen that the cleaning of the sprinkler filter device 1 does not adversely affect the water treatment capacity.

In addition, FIG. 9 shows the change over time in COD. Curve p is the concentration in the wastewater W flowing into the circulating nitrification denitrification system 2A and 2B, curve q is the concentration in the treated water P in the circulating nitrification denitrification system 2A, and curve r is the concentration in the circulating nitrification denitrification system. It is the concentration in the treated water P in 2B. Further, FIG. 10 shows the change over time of SS. The curve s is the concentration in the waste water W flowing into the circulating nitrification denitrification system 2A and 2B, the curve t is the concentration in the treated water P in the circulating nitrification denitrification system 2A, and the curve u is the circulation nitrification denitrification system. It is the concentration in the treated water P in 2B.

From FIGS. 9 and 10, no deterioration in water treatment performance was observed in the circulating nitrification denitrification system 2A. Therefore, from the viewpoint of COD and SS, it can be seen that the cleaning of the sprinkler filter device 1 does not adversely affect the water treatment capacity. Further, in the circulation type nitrification denitrification system 2B, the accumulated sludge trapped in the filter medium 32a in the watering filter bed 32 was peeled off and its outflow occurred on the way, and the temporary deterioration of COD and SS was observed. In the circulation type nitrification denitrification system 2A, this did not occur, and the film of aerobic microorganisms on the surface of the filter medium 32a was maintained in an appropriate state, and the water treatment capacity was maintained.

The sprinkling filter device and the cleaning method thereof according to the embodiment of the present invention have been described above, but the present invention is not limited to the one described in the above-described embodiment, and the scope of the matters described in the claims. Various design changes are possible within.

1 Watering filter 2 Water circulation type nitrification and denitrification system 3 Watering filter body 31 Watering filter outer cylinder 32 Sprinkling filter 32a Filter material 33 Support 34 Pipe fixture 35 Lower discharge pipe 36 Three-way cock 4 Water flooding equipment 41 Washing water injection pipe 42 Cock 43 Pump 44 Upper discharge pipe 5 Cleaning air aeration equipment 51 Air injection pipe 52 Cock 53 Air pump 6 Settling device 7 Anoxic filter A A Air C Washing water P Treated water W Drainage

Claims (5)

The main body of the sprinkler filter that accommodates the sprinkler filter formed of a large number of filter media, performs waste treatment during wastewater treatment, and discharges the treated water to the oxygen-free filter device, and the sprinkler filter with washing water during cleaning. A sprinkler filter device that periodically cleans a sprinkler filter device including a flooding facility for cleaning that is flooded and an air exposure facility for cleaning that air-explodes the sprinkling filter that is flooded with the wash water. It ’s a cleaning method,
At the time of cleaning, the cleaning water is injected by the cleaning equipment to flood the sprinkler filter bed, and then the water sprinkler filter bed is air-exposed by the cleaning air aeration equipment to adhere to the filter medium. The larvae and eggs are promoted to peel off, and then the washing water containing a part of the 蠅 is discharged from the upper part of the watering filter bed to the settling device, and then the washing water containing the rest of the 蠅 is discharged from the lower part of the watering filter bed. A method for cleaning a sprinkler filter device, which comprises discharging washing water to the settling device . A main body of a sprinkling filter device that accommodates a sprinkling filter formed of a large number of filter media and performs wastewater treatment, a cleaning flooding facility that floods the sprinkling filter with washing water at the time of washing, and a flooding facility using the washing water. A method for cleaning a sprinkling filter, which periodically cleans a sprinkling filter equipped with an air aeration device for cleaning that blows air on the sprinkled filter.
After the washing water is injected by the washing water flooding facility to flood the watering filter bed, the watering filter bed is air-exposed by the washing air aeration facility, and the larvae of the flies attached to the filter medium The amount of washing that promotes the peeling of eggs and then accumulates from the upper surface of the watering filter bed to a depth of 50 mm or more and is equal to or less than the amount accumulated from the upper surface of the watering filter bed to a depth of 400 mm. A method for cleaning a sprinkling filter device , which comprises discharging water from the upper part of the sprinkling filter and then discharging the washing water from the lower part of the sprinkling filter. In the watering filter cleaning method according to claim 1 or 2 .
A method for cleaning a sprinkler filter device, which comprises using tap water, well water, or treated wastewater as the washing water used for flooding. A main body of a sprinkling filter device that accommodates a sprinkling filter formed of a large number of filter media and performs wastewater treatment, a cleaning flooding facility that floods the sprinkling filter with washing water at the time of washing, and a flooding facility using the washing water. A method for cleaning a sprinkling filter, which periodically cleans a sprinkling filter equipped with an air aeration device for cleaning that blows air on the sprinkled filter.
The filter medium is made of a cylindrical plastic having a diameter of 10 to 30 mm and a length of 10 to 30 mm.
After injecting the washing water by the washing water flooding facility and flooding the sprinkling filter bed, the air volume is 0.6 to 1.0 m ³ / m ² · min by the washing air air exposure facility, and the air exposure is performed. The watering filter is characterized in that the watering filter bed is air- exposed to promote the peeling of the larvae and eggs of the flies attached to the filter medium, and then the washing water is discharged. Floor equipment cleaning method. In the watering filter cleaning method according to any one of claims 1 to 4 ,
A method for cleaning a sprinkling filter device, which comprises periodically cleaning the sprinkling filter portion at least once every three days.

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