JP2001239296A - Polluted river cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable cleaning operation stably for a long period of time by suppressing the growth of biological membranes of filer media in a cleaning plant and eliminating the clogging of the filter media 21. SOLUTION: This polluted river water cleaning device has a river water introducing waterway which is introduced with the polluted river water as treated water and discharges the water, filter media 21 which are immersed in the treated water into the river water introducing waterway and are adhered with a microbial film having a polluted water cleaning effect and plants 17 which expand their roots to the filter media 21 and are planted into granular materials 20 laid on the filter media 21 so as absorb the nutrient-components sticking to the filter media 21. Such plants 17 are adequately plants (papyrus, reeds, kenaf, rapes, etc.), having vigorous propagation power under the aquatic environment. One piece or plural pieces of air diffusion pipes 18 for sending air into the waterway from a blower are laid near the bottom of the river water introducing waterway.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polluted river purifying apparatus for purifying polluted rivers, and more particularly to a method for combining the removal of nutrients by microorganisms and the treatment of biofilms and waste products to which filter media is attached. The present invention relates to a polluted river purification device for stabilizing and maintaining polluted river water purification treatment and preventing eutrophication of rivers flowing into inland seas and lakes.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for environmental protection, and accordingly, prevention of pollution of inland seas, lakes and marshes and inflowing rivers has been increasing.
Significant effects have been achieved, such as improvement of water quality transparency through national efforts such as the enactment of the Water Pollution Control Law. Among them, unfortunately, there is no effective means for preventing eutrophication, especially for economical removal of nitrogen and phosphoric acid. Therefore, eutrophication of inland seas, lakes and inflowing rivers has been Only possible by purification.

[0003] In the purification of such influent wastewater, there has been already known an example in which the purpose of removing nitrogen and phosphoric acid has been achieved by using a commercially available combined treatment septic tank and a commercially available useful microorganism in combination. This useful microorganism has been marketed since the 1950's, and has been subsidized by municipalities for the purpose of preventing odors in toilets, eliminating clogging of sewage drainage pipes, and converting human waste and animal excrement into organic fertilizer. In recent years, it has been used in particular to eliminate the bad smell of livestock pollution and also to breakthrough wastewater with a simple filter bed purification system, making a remarkable achievement in preventing environmental degradation. Is what it is.

[0004] Further, as other conventional techniques, there are already known ones in natural septic tanks and public sewage wastewater treatment plants that achieve their purpose by utilizing natural microorganisms. It is actually used. In particular, purification of small and medium-sized rivers having a high degree of pollution has become a serious problem in the watershed of a water supply source. Even for these highly contaminated small and medium-sized rivers, a net-shaped container is filled with filter media such as porous ceramics and charcoal, immersed in the running water of the river, and an aeration device is set in the middle of the river flow path. The combination of environmental and anaerobic environments has been successful in decomposing and removing pollutants with microorganisms.

[0005]

However, as a problem, sludge accumulates in the flow channel, and a microbial film is generated on the surface of the filter medium. Then, the microbial membrane gradually enlarges, increases in thickness, eventually peels off, and further enters the gap between the filter media. Then, water flow will be hindered,
The purification plant will be inoperable. This maintenance involves a great deal of trouble and cost, and results in an increase in the operating cost of the purification plant.

Therefore, in the present invention, in view of the problems in the prior art for the purpose of purifying the highly polluted medium and small rivers as described above, the growth of the biofilm of the filter medium in the purification plant is suppressed.
It is an object of the present invention to provide a polluted river purification device capable of performing a stable purification operation for a long period of time without clogging of a filter medium.

[0007]

According to the present invention, in order to achieve the above-mentioned object, the roots are extended to the filter medium 21 to which the biofilm is attached, which is immersed in the treated water of the river water introduction water channel 15, and the filter medium 21 is provided. A plant 17 adapted to the environment of the polluted water area to decompose the biofilm attached to the vegetation and absorb it as nutrients is vegetated.
It is intended to be removed. This prevents the biofilm attached to the filter medium 21 from being enlarged and the filter medium 21 from being clogged, thereby enabling a stable operation of the processing apparatus. Furthermore, by using the plant 17 to be vegetated as a resource, the resource is produced with the treatment of the polluted river water.

That is, the polluted river purifier according to the present invention is provided in the middle of a polluted river, and purifies and discharges river water. The polluted river water as treated water is introduced and discharged. A water introduction channel 15; a filter medium 21 immersed in the treated water in the river water introduction channel 15 to attach a microbial membrane having a sewage purification effect; and a root extending to the filter medium 21 to remove nutrients attached to the filter medium 21. And a plant 17 vegetated so as to absorb water.

In such a polluted river purification apparatus, the filter medium 2
1, the plant 17 is vegetated so as to absorb the nutrients attached to the filter medium 21, so that the biofilm to be attached to the filter medium 21 and to be deposited is decomposed and absorbed by the roots of the plant 17. Go. This can prevent an increase in the biofilm attached to the filter medium 21. From the viewpoint of the food quality of the plant 17, the plant 17 is a plant that is originally adapted to a polluted water environment and vigorously propagates in such an environment, and can be used as a resource.
For example, kenaf and papyrus selected in the US textile crop search project from 1960 to 1971 show high purification power and CO ² reduction ability.

A filter medium 21 is housed in a mesh basket 16 immersed in the treated water in the river water introduction channel 15, and a fine granular material 20 is laid on the filter medium 21 in the mesh basket 16,
The plant 17 is vegetated. By doing so, the plant 17
Can be vegetated in a stable posture, and the roots of the vegetated plant 17 can be reliably extended to the filter medium 21 below the granular material 20.

As described above, the plant 17 which is adapted to the polluted water environment and vigorously propagates in that environment is a type of plant which is inherently less likely to cause root rot. However, an air diffuser 18 is provided in the river water introduction channel 15, and the diffuser 18
The aerated environment and the anaerobic environment are alternately brought about by passing water through the treated water in the river water introduction channel 15 by diffusing the treated water in the river water introduction channel 15 through Helps activate.

In addition, when the polluted river water as the treated water is pre-treated, such as settling, into the river water introduction water channel 15 and treated water with reduced pollution is introduced, the biofilm adhered to the filter medium 21 can be prevented. Therefore, the plant 17 can balance the biofilm removal ability of the filter medium 21 with the amount of biofilm attached, thereby enabling stable operation.

[0013]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 is a diagram showing the entire polluted river purification plant.
Treated water flowing through small and medium-sized rivers with high turbidity is first stored in the sedimentation basin 1. The flow rate of the treated water in the sedimentation basin 1 is close to 0, and the sediment of the treated water precipitates therein. The sedimentation basin 1 is preferably provided with a plant cultivation raft as described in Japanese Patent Application Laid-Open No. H11-332405, and water quality is obtained by natural purification action of plants such as papyrus and kenaf vegetated on the plant cultivation raft. To improve

The supernatant of the treated water from the sedimentation basin 1 is sent to the anaerobic tank 2 through the drain gutter 5. In the anaerobic tank 2, a sludge sedimentation net is provided near the bottom thereof, and a portion above the sludge sedimentation is constantly or always stirred by the stirrer 6. Further, the treated water in the anaerobic tank 2 is placed in an anaerobic environment, in which anaerobic bacteria propagate, and some of the pollutants floating in the treated water are decomposed and removed by the anaerobic bacteria. You. The dead anaerobic bacteria settle down as sediment, and accumulate on the bottom of the anaerobic tank 2 through the sludge sedimentation net. A sludge discharge pipe 12 is connected to the bottom of the anaerobic tank 2 via a valve 13. By opening the valve 13, the sludge deposited on the bottom of the anaerobic tank 2 can be pulled out.

Out of the treated water in the anaerobic tank 2, the water at the top is sent to the aerobic tank 3 through a water pipe 7. In this aerobic tank 3, a sludge sedimentation net 25 is stretched near the bottom, and the upper part is constantly or occasionally stirred by the stirrer 9. The treated water in the aerobic tank 2 includes
Sludge sedimentation net 25 from blower 10 through air pipe 11
The air is scattered around the area, which puts it in an aerobic environment. Therefore, aerobic bacteria proliferate inside the aerobic tank 3, and some of the pollutants floating in the treated water are decomposed and removed by the aerobic bacteria. The dead aerobic bacteria settle as a sediment, and accumulate on the bottom of the aerobic tank 3 through the sludge sedimentation net 25. A sludge discharge pipe 12 is connected to the bottom of the aerobic tank 3 via a valve 13. By opening the valve 13, the sludge deposited on the bottom of the aerobic tank 3 can be pulled out.

The treated water below the middle part of the aerobic tank 3 is:
After being returned to the anaerobic tank 2 through the reverse feed pipe 8 provided with the pump 26 and subjected to the anaerobic treatment again, it is sent again to the aerobic tank 3 as treated water. The treated water in the upper part of the aerobic tank 3 is sent to the polluted river purification apparatus according to one embodiment of the present invention through the drain pipe 14. Japanese Patent Application Laid-Open No. 8-108189 discloses a filter bed of a purification apparatus according to the invention of the present inventor. However, such a filter bed may be used, and a filter bed without a ceiling plate may be used. Can be used.

This polluted river purifying apparatus 4 has a slender river water introduction channel 15 formed by a long groove or box. FIG. 1 shows the starting point side, that is, the end on the inflow side of FIG. And FIG. 3 shows the end point, that is, the end on the outflow side. In the illustrated example, an elongated river water introduction channel 15 is formed by a long box, but this may be a simple groove.

Near the bottom of the river water introduction channel 15,
One or a plurality of air diffusers 18 are provided to send air from the blower 10 into the water channel and diffuse the air. Blower 10
Is sent to the bottom of the river water introduction channel 15 through the air diffuser 18, and from a number of air diffusion holes (not shown) provided in the peripheral wall of the air diffuser 18, the water is supplied to the river water introduction channel 15. Air is evenly diffused by the portion of the inner diffuser tube 18 between the mesh baskets 16. As a result, the river water introduction channel 15
The treated water in is placed in an alternating state of aerobic and anaerobic.

A net basket 16 having a cubic storage space substantially equal to or slightly smaller than the inner width of the river water introduction channel 15 is immersed in the river water introduction channel 15 at appropriate intervals. . As shown in FIG. 3, the net basket 16 has a shape in which the bottom and the periphery are surrounded by a net, and the top surface is open. The net baskets 16 are placed at appropriate intervals in the river water introduction water channel 15.

The mesh basket 16 is filled with a filter medium 21 made of a porous ceramic, another porous inorganic material, a porous synthetic resin material, or the like. Then, fine particles 20 such as fine zeolite particles and quarries are laid on the upper part of the mesh basket 16 so as to cover the filter medium 21.
Is covered.

The particulate matter 20 has a plant 1 adapted to the environment of a polluted water area, such that roots are extended to a filter medium 21 thereunder, and biofilms attached to the filter medium 21 are decomposed and absorbed as nutrients.
Vegetation 7 As such a plant 17, for example, a plant that has a root that extends below a wetland such as a papyrus, a reed, a kenaf, and an oil vegetable or a waterside or the like and has a strong fertility in an aquatic environment is suitable. The biofilm adhered to the filter medium 21 is decomposed and removed by the plant 17 to prevent the biofilm of the filter medium 21 from being enlarged and the filter medium 21 from being clogged. .

Papyrus (paper mosquito net hanging) is a large perennial plant belonging to the family Cyperaceae and is aqueous, and is native to tropical Africa such as North Africa. The cross section of the stem is triangular and grows to a height of about 2.5 m, with many total bracts and many light brown spikelets on the stem apex. It is thriving in the lower Nile and is famous for making paper by squeezing stalks in ancient Egypt.

Kenaf is an annual herbaceous plant of the family Malvaceae.
It is native to India and is grown in China, the USSR and the southern United States. It grows to a height of 2 to 5 m, leaves are palm-shaped, flowers are yellow, and their cores are dark red fruits. The fibers of the stem resemble jute and are used as a raw material for ropes, fabrics and paper.

Reeds are perennials of the Poaceae family. It is native to the waters of various places and is the most widely distributed plant in the world. Run large flat rhizomes in the ground to create large communities. It grows to a height of about 2m, has stems, and leaves are bamboo leaf-shaped. In the fall, spikelets consisting of numerous fine violet florets emerge. The stem is used as a material for the curtain.

The oil vegetable is a biennial plant of the Brassicaceae family, large in size, and the whole plant is slightly white. It is cultivated all over the world as a crop, but its origin is in Europe. The native species is the mother species of many leafy vegetables such as Komatsuna, Chinese cabbage and turnip. Another species is oilseed rape, which is taxonomically distinct from native species. At present, oilseed rape is widely cultivated instead of native species. Rapeseed oil is taken from the seeds. The leaves are edible as winter vegetables, the flowers are ornamental and used as feed.

These plants 17 root on soil that is naturally moist or submerged, and grow using the organic matter in the soil as nutrients. At this time, the sludge containing dead microorganisms is decomposed and absorbed by organic acids secreted from the roots. Therefore, these plants 17 are divided into granules 20 so that the roots of the plants 17
The roots of the plant 17 decompose and remove the biofilm attached to the filter medium 21 by vegetation. Thereby, the filter medium 21
Sludge is reduced and clogging of the filter medium 21 is reduced,
Stable operation becomes possible.

It is also effective to change the type of plant 17 to be vegetated and cultivated according to the season. For example, kenaf vegetation in summer and oilseed vegetation in winter. Also,
For plants 17 such as kenaf, which have good root growth in dark areas where sunlight does not reach, the upper surface of the river water introduction channel 15 is covered with a black light-shielding film or the like, and the roots of the plants 17 are shaded. Then it is effective. Kenaf and papyrus cultivated in this way can be used as a raw material for various fiber products, and oily vegetables can be used as a raw material for edible, ornamental or rapeseed oil as described above, so that sludge can be indirectly recycled as resources. Become.

The outflow side, which is the end point of the river water introduction channel 15, is shown with part of the water removed in FIG. 2, and as shown in cross section in FIG. A water discharge pipe 19 for discharging the portion is provided, and the treated water is discharged. The treated water that has been purified until the degree of pollution becomes equal to or less than a required value is released to, for example, a river.

The situation in the actual operation of this polluted river purification apparatus will be described below with reference to actual examples. In the above-mentioned polluted river purifier, when the flow of treated water was started without vegetation of the plant 17, about 10 months after the start of water flow, a situation where polluted water overflowed from the purified water channel occurred and overflowed to the younger brother. Water volume increased.

Therefore, when kenaf seedlings were vegetated on the granular material 20 as the above-described plant 17, white fine roots of kenaf extended around the gap of the filter medium 21 made of porous ceramic balls and around the air diffuser 18 in three weeks. In this condition, biofilm enlargement was eliminated, sludge accumulation decreased, and flooding stopped.

In the river water introduction channel 15 in which the sunlight is shielded by a black film or the like, the roots of the kenaf are stretched very vigorously, and there is a great difference in the rooting as compared with the channel where sunlight can enter. The growth of kenaf was 3.5 m on the raft of the sedimentation pond 1 at the upstream, but reached 5 m in the river water introduction channel 15 of the above-mentioned polluted river purification apparatus, and high-quality kenaf was obtained.

After the plant 17 was vegetated and its roots extended to the filter medium 21 as compared to before the plant 17 was vegetated, the amount of treated water in the river water introduction channel 15 was increased by a factor of five. The cultivation density of kenaf was increased 7 to 10 times as compared with kenaf vegetated on the cultivation raft described above. Furthermore, the measured value of the treated water quality is not much different from that before the filter medium 21 of the river water introduction channel 15 is clogged.

As described above, kenaf was vegetated in the summer so that the roots of the plant 17 were extended on the filter medium 21 of the river water introduction channel 15, but oilseed plants were vegetated in the winter. In this situation, in addition to the purification of the treated water by the microorganisms attached to the filter medium 21, the removal efficiency of nitrogen and phosphorus contained in the treated water is lower than that of a purification device that does not vegetate the plants 17 due to the absorption of pollutants by the plants. An increase of 20% to 80% was confirmed. During the winter season when plants cannot grow, the nitrogen removal rate decreases significantly, but the phosphorus removal rate does not decrease so much, and the summer removal rate is 60%.
It has been confirmed that it is maintained in the range of ~ 80%.

The existence of highly polluted water areas in the so-called Dob River state is a serious problem. For example, in the Kasumigaura basin of Ibaraki Prefecture, its pollution degree is said to reach 9 billion yen per year in terms of chemical fertilizer. . If the water in such a polluted water area can be purified by cultivation of kenaf or oilseed vegetables, it becomes possible to recycle the plant 17 as well as to purify the polluted water. For example, kenaf can be used as a paper resource, and rapeseed oil can also be used as a diesel fuel for oilseed vegetables. In particular, it was found that rapeseed vegetation, which is suitable for winter cultivation, is useful for phosphorus removal even in winter.

The anaerobic tank 2 and the aerobic tank 3 are omitted, and even if water is directly passed from the sedimentation basin 1 to the river water introduction channel 15 of the polluted river purification apparatus 4 according to the present invention, the kenaf Is 5
m. However, the color of the kenaf leaves was paler than when sent from the sedimentation basin 1 to the river water introduction channel 15 through the anaerobic tank 2 and the aerobic tank 3 described above, and a difference in the nitrification degree appeared. In both cases, ammoniacal nitrogen and nitrite-based nitrogen had been purified to a state where measurement was difficult.

[0036]

As described above, according to the present invention, the roots are extended to the filter medium 21 and the plants 17 are vegetated so as to absorb the nutrients attached to the filter medium 21, so that the plants 17 adhere to and accumulate on the filter medium 21. Is decomposed and absorbed by the roots of the plant 17. This can prevent an increase in the biofilm attached to the filter medium 21. In particular, the plant 17 is a plant that is originally adapted to a polluted water environment and vigorously breeds in such an environment, and if a plant that can be used as a resource is used, the production of resources as well as the purification of polluted river water can be achieved. Can be done simultaneously.

At present, the government is pursuing purification using conventional vegetation such as reeds and asaza by wave-dissipation. This cost is 300 million yen / km. For example, on the Kasumigaura coast, 250 km × 300 million yen = 75 billion yen is required. On the other hand, according to the polluted river purification apparatus of the present invention as described above, there is a possibility of considerable cost reduction.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a polluted river water purification system using an example of a polluted river water purification device according to the present invention.

FIG. 2 is a perspective view of an outflow side showing an example of the polluted river water purification device.

FIG. 3 is a vertical side view of an outflow side showing an example of the polluted river water purification device.

[Explanation of symbols]

 15 River water introduction channel 21 Filter media 17 Plant 16 Net basket 20 Granular material 18 Air diffuser

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B314 MA23 MA62 ND03 PB02 PB44 PB64 PC03 PC08 PC18 PC19 PC25 PD19 PD27 PD57 4D003 AA01 AB11 BA02 CA07 CA08 EA24 EA30 4D029 AA01 AB05 BB11 DD03 DD05 4D040 BB51 CC52 BB52

Claims (5)

[Claims] Claims: 1. A polluted river purifier installed in the middle of a polluted river for purifying and discharging river water, wherein the polluted river water is introduced as treated water and discharged therefrom.
5), a filter medium (21) immersed in the treated water in the river water introduction channel (15) to attach a microbial membrane having a sewage purifying action, and a root extending to the filter medium (21), 21) A polluted river purification apparatus, comprising: a plant (17) vegetated to absorb nutrients attached to the river. 2. The filter medium (21) is a river water introduction channel (15).
The polluted river water purification apparatus according to claim 1, wherein the apparatus is contained in a net basket (16) immersed in treated water in the inside. 3. A fine granular material (20) is spread on a filter medium (21) in a net basket (16), a plant (17) is vegetated on the granular material (20), and a root of the plant (17) is vegetated. 3. The polluted river purification system according to claim 1 or 2, characterized in that the stretches into the filter medium (21) below the particulate matter (20). 4. An air diffuser (1) in the river water introduction channel (15).
8) is piped, and the treated water in the river water introduction channel (15) is diffused through the diffuser pipe (18) to maintain the treated water in the river water introduction channel (15) in an aerobic environment. The polluted river purification apparatus according to any one of claims 1 to 3, wherein: 5. The river water introduction channel (15) is disposed at a position where pretreated water, which is polluted river water, which is treated water, is introduced to reduce the pollution. The polluted river purification device according to any one of claims 1 to 4.