JP2001157897A - Method and apparatus for improving water quality - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the water quality improving efficiency of a biological filter bed. SOLUTION: A container 2 having a living waste water finflow port 4 and an outflow port 2 is opened upwardly and the width 9 of the container 2 is formed so as to become small from the upper part thereof to the lower part thereof and a plurality of cylindrical biological filter beds 17 formed from a fibrous material are arranged in the container 2 in a tiered state and the arranging density of these biological filter beds 7 is made gradually small from an upper tier to a lower tier and the bottom 11 of the container 2 is inclined low from one end thereof to the other end thereof and a discharge pipe 21 discharging a deposit and a drain valve 22 are provided to the bottom 1 on the other end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for improving the quality of contaminated water, and more particularly to a method and an apparatus for removing contaminants in water using living organisms.

[0002]

2. Description of the Related Art Water quality in semi-closed water bodies such as ponds, swamps, lakes and some rivers has become serious. In particular, the above tendency is remarkable in a region where urbanization has rapidly progressed due to an increase in population inflow. The situation is the same not only in Japan but also in urban areas of developing Asian countries such as China, Thailand and Vietnam.

The main cause of water pollution, that is, eutrophication, is the inflow of domestic wastewater. Specific pollutants are spoiled organic matter and green algae (water bloom). Various measures have been proposed as follows to remove these.・ Aeration (aeration, bubbling, fountain) ・ Generate microbubbles ・ Inject ozone ・ Apply ultrasonic waves (cavitation) ・ Install activated carbon ・ Install charcoal (corn) ・ Forced water circulation ・ Plant reeds etc. These methods Is not universal for all water bodies and pollution situations. Considering the size of the polluted area, the degree of pollution, energy cost, operability and maintainability, the fact is that it is advantageous and disadvantageous.

There is a means called a biological filtration method (biological filtration method). This is a method to set up a biological filter bed suitable for living organisms, especially microorganisms, in polluted waters. Bacterial biofilms form on the biological filter, and the daphnia that inhabits them breed. Bacteria and daphnia prey on contaminants such as spoiled organic matter and green algae. Therefore, the biological filter is characterized in that organisms suitable for improving the water quality for the water area breed. Compared to ozone injection and ultrasonic method, this method is gentler and uses the natural purification function and has less impact on the environment. Further, there is an advantage that the energy cost during operation is small.

[0005]

FIG. 11 is a perspective view showing an example of a prior art water quality improvement device. This water quality improvement device 50 hangs a plurality of biological filter beds 52 in a box-shaped container 51 and circulates domestic wastewater (contaminated water) targeted for water quality improvement inside the container 51 to remove contaminants. It is taken out as the domestic wastewater 54 after the treatment.

However, this water quality improvement device 50 is
1 has a problem that the whole biological filter 52 does not function efficiently. That is, the effect of improving water quality is not uniform in the height (longitudinal) direction of the container 51. Attempts have been made to aerate (bubble) or agitate with an underwater propeller in order to achieve uniformity, but this is problematic from the viewpoint of increasing energy costs and performing long-term reliable operation. Further, sludge-like deposits 55 are deposited on the bottom of the container 51, but it is necessary to periodically discharge the deposits and clean the inside thereof, so that maintenance work is not easy.

[0007] It is an object of the present invention to improve the water quality improvement efficiency of a biological filter.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of forming a fibrous material from a position close to a water surface in a flow path of a contaminated water opening upward or in a water of a contaminated water area. The biological filter is arranged hierarchically and the density of the biological filter is gradually reduced from the upper layer to the lower layer, and the organisms living on the biofilm generated on the biological filter or Water quality is improved by predating or decomposing contaminants of contaminated water on living organisms living in water.

[0009] The contaminated water flow path or the contaminated water area is open upward, so that the sunlight is sufficiently irradiated. For this reason, the position close to the water surface is suitable for living organisms because the water is warm and the oxygen content in the water is high, except when the water temperature rises extremely in summer. This increases the population density of bacteria and daphnia, and also enhances their vitality. On the other hand, at a position away from the water surface in the depth direction, the sunshine is weak and the water temperature is low, so that the density of living organisms is low and the vitality is low.

[0010] With respect to the flow path or the contaminated water area of the contaminated water, a biological filter made of fibrous material is hierarchically arranged from a position close to the surface of the water toward the water bottom. By gradually decreasing the arrangement density from the upper level to the lower level, a thick biofilm inhabiting bacteria and daphnia grows around the fibers of the biofilter near the water surface. At the same time, more organisms inhabit the water near the water surface. Organisms such as bacteria and daphnia that have multiplied prey or decompose organic decay substances and green algae, so that these organic decay substances and green algae are reduced, and water quality is improved. Furthermore, since the biological filter bed is arranged near the water surface with an increased density, the number of living organisms increases and the speed of improving the water quality is high. The further away from the water surface, the thinner the biofilm around the fibers of the biological filter and the less creatures in the water. Therefore, predation and decomposition of organic decay products and green algae by these organisms are reduced, and the rate of improvement in water quality is small. Therefore, the water quality improvement efficiency of the placed biological filter bed as a whole is enhanced.

Further, the present invention provides a container having an inflow port provided at one end and an outflow port provided at the other end, and a fibrous material stretched between one end and the other end of the container. A plurality of biological filters, wherein the container is opened upward,
The width of the container is formed to be smaller from top to bottom, and the biological filter is provided hierarchically in the container, and is gradually arranged from the upper layer to the lower layer. And

By doing so, the water quality of the contaminated water passing through the container is, as described above, the surface of the biological filter made of fibrous material and the surrounding living organisms living in the water. It can be improved by predation and decomposition, and the water quality improvement efficiency can be increased. Furthermore, by inclining the bottom of the container from one end side to the other end side, deposits deposited on the bottom of the container can be easily moved from one end side to the other end side, and can be accumulated at the other end side. . In this case, a means for discharging the accumulated deposit is preferably provided at the other end of the container. Thus, the sediment can be easily discharged to the outside of the container, and the inside of the container can be purified, so that the maintainability can be improved.

In the present invention, the form of the biological filter formed of fibrous material is not particularly limited. For example, a material in which fibers are entangled, a material in which fibers are knitted, a cloth material in which fibers are woven, etc., are formed into a shape such as a string, a rod, a cylinder, a hollow square or a flat plate, and are formed long in one direction. Is done. The arrangement density of the biological filter bed means the amount of the biological filter bed arranged per unit volume in water. Therefore, when the biological filter is, for example, a string-like member or a cylindrical member,
The number of arrangements at the same height position is sequentially reduced from the position close to the water surface toward the water bottom. When the biological filter is a plate-like member having a width in the horizontal direction, the width can be gradually reduced from a position close to the water surface toward the water bottom.
By doing so, the arrangement density of the biological filter can be changed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a method and apparatus for improving water quality according to the present invention will be described in detail with reference to the drawings. 1 to 10, the same or equivalent parts are denoted by the same reference numerals.

FIG. 1 is a longitudinal sectional view showing an embodiment of the water quality improving apparatus according to the present invention. 2 is a cross-sectional view taken along line II of FIG. 1, and FIG. 3 is a plan view of FIG.

The water quality improvement device 1 of the present embodiment includes a pond, a swamp,
This material is used to improve the water quality of lakes, dams and rivers. The material whose apparent surface area is increased by weaving fibrous substances is used as a high-density habitat for microorganisms and small animals, a so-called biological filter, and is used for domestic wastewater (contaminated water). ) Is installed in the supply channel or contaminated water area to improve water quality by decomposition of spoilage organic matter in water by water and predation and decomposition of green algae.

That is, the water quality improvement device 1 introduces the domestic wastewater 42 to be improved in water quality into the one end 13 of the container from the upstream part of the container 2, improves the water quality and treats the treated wastewater 44 from the other end 14. Is discharged as Further, the water quality improving device 1 comprises a container 2 having an inflow port 4 provided at one end 13 and an outflow port 5 provided at the other end 14, and a fiber wrapped between one end 13 and the other end 14 of the container. And a biological filter bed 17 which is a member formed of a material.

The container 2 is opened upward, the width 9 is formed to be smaller from top to bottom, and the cross section is a substantially inverted triangle, so-called hopper shape. Further, the container 2 has its bottom 11
Is inclined downward from one end 13 toward the other end 14. Further, a discharge pipe 21 and a discharge valve 22 are provided at the bottom 11 on the other end side of the container 2 as means for discharging the sludge-like precipitate (sediment) 46 generated from the contaminated water.

The biological filter bed 17 is moved from one end 13 side to the other end 14 side.
Toward the side, it is wrapped substantially horizontally along the flow of the contaminated water. The containers 2 are arranged hierarchically in the depth direction, and the arrangement density of the biological filter beds 17 is gradually reduced from the upper layer to the lower layer, and the number of the biological filter beds 17 is reduced. Further, in the present embodiment, the biological filter bed 17 is formed by knitting fibers and has a substantially cylindrical shape, and is stretched in the container 2 so as to be parallel to the flow of domestic wastewater. The shape of the biological filter 17 is not limited to the cylindrical shape as described above, but may be a rod shape or a string shape.

As shown in FIG. 2, the cross section (or cross section in the width direction) of the container 2 is substantially triangular.
The more biological filter beds 17 are provided, the fewer at the bottom (lowest level). In the case of the present embodiment, a total of five rows of biological filter beds 17 are provided in the height direction of the container 2.

In the process of water quality improvement, the water quality improvement device 1 causes the domestic wastewater 42 to flow while contacting the surface of the biological filter bed 17. At this time, spoilage organic matter is decomposed by the action of bacteria and the like, and contaminated water is removed. Be purified. If the contaminated water flowing into the water quality improvement device 1 is water containing an excessive amount of green algae, daphnia (for example, Daphnia magna) living on the biological filter bed 17 actively eats blue water to purify the water. As described above, even if the biological filter 17 is made of the same material, microorganisms that eliminate the contamination inhabit according to the type and situation of the contaminated water flowing in.

As shown in FIG. 1, the bottom 11 of the container is shaped to be lower toward the downstream side. Therefore, the sludge-like sediment 46 precipitates and accumulates on the bottom of the container 2 on the outlet side. Since the discharge pipe 21 and the discharge valve 22 are provided at the bottom of this container, the sludge-like sediment 46 can be drawn out of the container 2 by opening and closing the discharge valve 22.

FIG. 4 is a system diagram showing an embodiment of the entire system of the water quality improvement device according to the present invention. It is an example showing the installation of the water quality improvement device 1 in the domestic drainage channel 30 into which the domestic drainage 42 flows. By pump 24
The domestic wastewater 42 is pumped from the domestic wastewater channel 30 and flows into the water quality improvement device 1 in which the biological filter bed 17 is provided. The domestic wastewater purified in the process of contacting the biological filter 17 is discharged from the water quality improvement device 1 as the treated domestic wastewater 44, and returns to the domestic wastewater channel 30. In this embodiment, the water quality improvement device 1 is provided side by side in the domestic wastewater flow path 30.
The water quality improvement device 1 itself can be directly immersed in the domestic drainage channel 30.

FIG. 5 is an explanatory diagram of the operation of the water quality improvement device of the present embodiment. This is a schematic drawing of the function of a biological filter and its basic characteristics as a cross-sectional view in the width direction of the apparatus. In the container 2 whose cross section is an inverted triangle,
The surface of the domestic drainage 42 opening at the upper end is wide and the sun 4
Sunlight from 8 is enough. On the other hand, since the vicinity of the surface of the domestic wastewater 42 is in contact with the atmosphere 49, air, particularly oxygen (O ₂ ) 49a, is dissolved in a large amount, and the O ₂ concentration is also reduced as shown in the O ₂ concentration distribution in the figure. It is higher than the bottom layer. Therefore, many biofilms 19 are formed on the six biological filter beds 17 provided at the upper part of the container 2.

The change in the amount of biofilm in the depth direction of the container 2 is shown at the right end of the figure. As is clear from this figure, it can be seen that more biofilms are formed above the container 2. Therefore, the water quality improvement device 1 of the present embodiment can effectively utilize the location where the activity of the microorganisms having the purification function is active, so that the purification ability is increased. Since the cross section of the container 2 has an inverted triangle shape, a sludge-like sediment 46 is necessarily deposited on the bottom of the container 2. These are easily drawn out of the system by operating the discharge valve 22.

FIG. 6 is a graph showing a comparison between the present embodiment and the prior art in which the density of suspended particles is reduced. FIG. 11 shows the density of suspended particles in water after the purification treatment.
Of the prior art water quality improvement device 50 (hereinafter the same) and the present embodiment (water quality improvement device 1).
The suspended particle density SS after the purification treatment on the vertical axis is dimensionlessly expressed by dividing by the suspended particle density SS ^* after the purification treatment in the conventional technology. In the prior art, SS /
SS ^* = 1.0. On the other hand, in the present embodiment, SS / SS ^* = 0.68, and it was confirmed that the water quality improvement device 1 of the present embodiment is more effective in reducing the suspended particle density. SS is plankton such as granulated spoiled organic matter and green algae. Spoiled organic matter is degraded by actively growing bacteria,
It is considered that green algae also decreased due to predation by daphnia and the like that became active.

FIG. 7 is a comparison diagram of turbidity expressed by a relative value in the present embodiment, the prior art, and no countermeasures. The turbidity of the contaminated water and the water after purifying the contaminated water are compared with the conventional technology and the present embodiment when no measures are taken. Turbidity is important because it affects the landscape of water bodies. Of course, it is strongly related to the physical properties of the SS.
The turbidity tu on the vertical axis in FIG. 7 was made dimensionless by dividing by the turbidity tu ^* when no measures were taken. When no countermeasure is taken, tu / tu ^* = 1. In the water quality improvement device 50 according to the related art, tu / tu ^* = 0.74. On the other hand, in the water quality improvement device 1 of the present embodiment, tu / tu ^* = 0.61.
It is. Thus, it has been proved that the purification performance is enhanced by implementing the present embodiment.

FIG. 8 is a comparison diagram of the COD expressed in the present embodiment, the prior art, and the relative value when no measures are taken. COD
(Chemical oxygen demand), which compares the characteristics of untreated water, the water quality improvement device 50 according to the prior art, and the water quality improvement device 1 of the present embodiment. Here, the notation COD is a symbol indicating the quantity.
The COD on the vertical axis is dimensionless by dividing by the COD at the time of no measures. In short, COD / COD ^* = 1.0 in the case of no contaminated water. On the other hand, in the water quality improvement device 50 according to the related art, the COD
/ ^COD * = a purification effect of up to 0.71. further,
In the water quality improvement device 1 of the present embodiment, COD / COD ^* =
It was 0.58, and it was confirmed that the purification effect was further enhanced.

When the water quality improvement device 1 is used for a long period of time, sludge-like sediment accumulates. So regularly,
It is necessary to perform maintenance such as removal and cleaning of the sludge-like precipitate. In such maintenance, the smaller the amount of water used for cleaning, the easier the maintenance.

FIG. 9 is a comparison diagram of the dimensionless water consumption between the present embodiment and the prior art. This is a comparison between the water quality improvement device 50 according to the prior art and the water quality improvement device 1 of the present embodiment in the amount of water used during maintenance. The amount of water used during regular cleaning Qw on the vertical axis was made dimensionless by dividing the amount of water used during regular cleaning Qw ^* in the prior art. In short, in the prior art, Qw / Qw ^* = 1.
It becomes 0. On the other hand, in the present embodiment, Qw / Qw ^* =
It is 0.34, and it is possible to greatly reduce the amount of water used, in other words, the amount of drainage. From the above results, the effect of implementing the present embodiment could be confirmed.

FIG. 10 is an explanatory view showing another embodiment of the water quality improvement device according to the present invention. In the previous embodiment, the mode in which the water quality improvement device 1 is installed in the inflow channel of domestic wastewater has been described. In this alternative embodiment, the water quality improvement device 1 is installed at the center of the reservoir 32. Even if countermeasures with biological filters are taken only at the inflow part of the reservoir, there is domestic wastewater that passes through it and there are contaminants that flow in with rainwater from various parts of the reservoir 32. It is effective to perform the purification treatment also in the above. The flow of water 34 at the center of the reservoir 32 is slow, and the residence time of the domestic wastewater in the biological filter bed 17 is sufficiently ensured, so that the effect of water purification can be improved.

The features of this embodiment described above are summarized as follows. (1) The purification efficiency of contaminated water increases when compared with biological filter beds of the same capacity. In other words, the processing amount can be increased. (2) The present invention can also exert its effect on drainage or water systems that have been excessively contaminated in connection with (1). (3) The sludge-like sediment deposited on the bottom of the biological filter bed can be easily discharged, and the maintenance work including the container of the biological filter bed can be performed quickly. (4) In connection with the feature of (3), even an unskilled person can operate and operate, and can be applied to water systems in various regions.

Although the present invention has been described in detail with reference to the illustrated embodiments, the present invention is not limited to only those embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, it goes without saying that a wide variety of modifications can be made.

[0034]

According to the present invention, the water quality improvement efficiency of the biological filter can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a water quality improvement device according to the present invention.

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a system diagram showing an embodiment of the entire system of the water quality improvement device according to the present invention.

FIG. 5 is an explanatory diagram of the operation of the water quality improvement device of the present embodiment.

FIG. 6 is a comparison diagram of the non-dimensional suspended particle density of the present embodiment and the prior art.

FIG. 7 is a comparison diagram of turbidity represented by a relative value according to the present embodiment, a conventional technique, and no countermeasures.

FIG. 8 is a comparison diagram of COD expressed by a relative value according to the present embodiment, a conventional technique, and no countermeasures.

FIG. 9 is a comparison diagram of the dimensionless water consumption of the present embodiment and the prior art.

FIG. 10 is an explanatory view showing another embodiment of the water quality improvement device according to the present invention.

FIG. 11 is a perspective view showing an example of a conventional water quality improvement device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water quality improvement apparatus 2 Container 4 Inlet 5 Outlet 9 Width 11 Bottom 13 One end 14 The other end 17 Biological filter bed 19 Biofilm 21 Drainage pipe (discharge means) 22 Drainage valve (discharge means) 32 Reservoir (contaminated water area) 42 Living Wastewater (contaminated water) 46 Sludge-like sediment (sediment)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yosuke Kajiyama 3-36 Takaracho, Kure-shi, Hiroshima Babcock Hitachi, Ltd. Inside Kure Research Laboratory (72) Inventor Kazuki Fujita 3-36 Takaracho, Kure-shi, Hiroshima Babcock-Hitachi, Ltd. F-term in Kure Research Laboratory (reference) 4D003 AA01 BA02 BA07 CA03 DA09 EA07 EA11 EA16

Claims (4)

[Claims] A biological filter made of fibrous material is hierarchically arranged from the position close to the water surface in the water path of the contaminated water or the water in the contaminated water area opened upward, and the biological filter is formed in a hierarchical manner. The arrangement density of the filter bed is gradually reduced from the upper layer to the lower layer, and the organisms living on the biofilm or the water living on the biological filter bed prey on the contaminants of the contaminated water or A method for improving water quality, comprising decomposing to improve water quality. 2. A container having an inlet provided at one end and an outlet provided at the other end, and a plurality of biological filters formed of fibrous material which are bridged between one end and the other end of the container. A floor, wherein the container is opened upward, the width of the container is formed to be smaller from top to bottom, and the biological filter bed is provided hierarchically in the container, Water quality improvement device that is gradually arranged toward the next level. 3. The water quality improvement device according to claim 2, wherein the bottom of the container is inclined downward from the one end to the other end. 4. The water quality improvement device according to claim 3, further comprising a discharge means for discharging sediment generated from contaminated water at a bottom of the other end of the container.