JP2772378B2 - Water purification equipment for closed water bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a closed water area provided in a relatively polluted water area such as a bay, a bay, a harbor, a lake or the like, or inland facing the water area. The present invention relates to a water purification system for a closed water body for purifying water in a building.

"Conventional technology" In recent years, ports near large cities have been reclaimed, watersides have been surrounded by artificial upright revetments, and seashores with priority on industry and functions have been formed.

For example, in Tokyo Bay, upright seawalls account for 65% of the coastline, and natural tidal flats are only 1-2%.
It just keeps the place. On the other hand, social needs are increasing every day to restore nature and create a hydrophilic space and amenity zone (comfortable and enjoyable life) to get close to water and restore life. .

By the way, for example, in the case of a closed water area completely closed from the surrounding sea area, there is no periodic water level fluctuation due to tide, so it is expected that the water quality will be purified by various organisms such as tidal flats If the water in the closed water area is kept for a long period of time, the water quality may deteriorate due to plankton multiplication or the like.

On the other hand, when purifying water, especially when using a microbial membrane, increase the surface area to which microorganisms are attached to increase the amount of the microbial membrane, and increase the contact speed to effectively contact the water to be purified with the microbial membrane. It is necessary to take a certain level or more, and to obtain a certain or higher dissolved oxygen concentration during purification by aerobic microorganisms.

"Problems to be solved by the invention" However, in the seaport areas of metropolitan areas where social needs are the greatest, such as the need to restore nature and restore life on the coastline, the water quality is particularly poor, so sea bathing and other marine leisure activities are difficult. Is often not suitable. In the sea area surrounding such metropolitan areas, landfills are advancing, and there are many canals whose water quality has deteriorated due to idleness.

In addition, when purifying seawater such as canals, a large amount of water with relatively low pollution compared to general wastewater is to be purified. Is not required, but fluid energy is required to obtain an appropriate contact speed with the microbial membrane. Therefore, when purifying the water quality of a canal or the like, it is not profitable if there is no technology for purifying a large amount of seawater at low cost, and it is necessary to secure sufficient flow energy at the lowest possible cost.

In the case of a closed seawater area, it is also conceivable to improve the water quality in the closed water area by periodically exchanging the water in the closed water area with seawater in the surrounding sea area. However, since the water quality in the closed water area is not improved more than the water quality in the surrounding sea area, if the water quality in the surrounding sea area is poor, even if the closed water area has a seawater exchange function, the water quality in the closed water area will not be improved. Can be improved to an appropriate water quality.

Therefore, recently, the exchange of water between the target closed water area and the surrounding sea area has been minimized and practically not performed.
Further, there has been a demand for the development of a technique for ensuring sufficient flow energy at low cost to generate an appropriate contact speed in the closed water area.

The present invention has been made in view of the above circumstances, and basically does not exchange water with a surrounding water area when purifying water in a closed water area closed from a surrounding water area such as a sea area, and naturally. It is an object of the present invention to provide a water purification system for closed water bodies that can efficiently purify water using energy.

[Means for Solving the Problems] The water purification system for closed water bodies according to the present invention includes a water-permeable biofilm that separates the closed water area into a plurality of areas in a closed water area closed from a surrounding water area. A region is provided, and in at least one of the regions, an opening communicating with the peripheral water region is provided, and in the region, water from the peripheral water region is connected to the opening. An expanding / contracting material whose volume changes according to the amount of introduction is provided in a submerged state.

[Operation] In the water purification apparatus for closed water bodies of the present invention, a water-permeable biofilm contact area for isolating the closed water area into a plurality of areas is provided in the closed water area closed from the surrounding water area, and An opening communicating with the peripheral water area is provided in at least one of the areas, and in the area, expansion and contraction that is connected to the opening and changes in volume according to the amount of water introduced from the peripheral water area. By providing the material in the submerged state, as described below, the tidal force of the surrounding water generates flow energy in the closed water area, and the flow energy causes the water in the closed water area to flow, thereby causing the biofilm. Pass through the contact area. At this time, the water passing through the biofilm contact area is purified by the organic matter decomposition action of the microbial membrane by maintaining the contact speed between the microorganism membrane immobilized in the biofilm contact area and water at an appropriate speed. I do.

In other words, when the water level in the surrounding water area rises due to rising tide from low tide to high tide, a water level difference occurs between the surrounding water area and the closed water area, and the potential energy due to the water level difference causes an opening from the surrounding water area. A flow of water through the section towards the closed body of water occurs, thereby causing water in the surrounding body of water to pass through the opening and into the interior of the expansion and contraction material. When water is introduced into the expanding / contracting material in this manner, the water level of the region where the expanding / contracting material is provided in the closed water area rises, and the water level between the region and the biofilm contact region is increased. A difference in water level occurs at the same time, and at the same time the water level in the biofilm contact area rises due to the water in the area flowing into the biofilm contact area due to the water level difference, whereby the biofilm contact area and the biofilm contact area A water level difference occurs between the opposite area isolated from the area, and the water level difference causes the water in the biofilm contact area to flow out to the area opposite to the area and the water level in the area also rises. It will go. In this case, the water that passes through the biofilm contact area passes through the biofilm contact area with the microbial membrane immobilized in the biofilm contact area while securing an appropriate contact speed, thereby decomposing the organic matter of the microbial membrane. It will be more effectively purified. And
In this way, when the surrounding water area becomes high tide, the water levels of all areas in the closed water area rise to the same water level as the water level of the surrounding water area.

In addition, when the water level of the surrounding water area descends due to ebb tide from high tide to low tide, a water level difference occurs between the surrounding water area and the closed water area, and the potential energy due to the water level difference causes the potential energy from the closed water area to the opening area. A flow of water is generated toward the surrounding water area through the opening, so that the water inside the expansion / contraction material provided in the closed water area flows through the opening to the surrounding water area. When the water inside the expansion / contraction material flows into the surrounding water area in this manner, the water level of the area in the closed water area where the expansion / contraction material is provided falls, and the area and the biofilm contact area And a water level difference is generated between the biofilm contact area and the water level in the biofilm contact area.
This causes a water level difference between the biofilm contact area and the opposite area isolated from the area by the biofilm contact area, and the water level difference causes the water in the area opposite to the area to be removed from the biofilm. After flowing into the contact area, the water level in that area also rises. In this case as well, the water passing through the biofilm contact area passes through the biofilm membrane immobilized in the biofilm contact area while maintaining an appropriate contact speed, whereby the organic matter of the microbial membrane is removed. It is effectively purified by the decomposition action. Then, in this way, when the surrounding water area becomes low tide, the water levels of all the areas in the closed water area fall to the same water level as the surrounding water area.

"Embodiment" Hereinafter, as a first embodiment of the present invention, a water purification system for a closed water body when the surrounding water area is a sea area will be described with reference to FIGS. 1 to 5. FIG.

As shown in FIG. 1, a water purification system for closed water bodies according to this embodiment has a surrounding sea area 2 surrounded by an outer wall 1 on all sides.
(Peripheral water area) for purifying water in the rectangular closed water area 3 closed from the surrounding water area, and extending in the closed water area 3 from a pair of outer walls 1 facing each other and arranged in parallel with each other. Two partitions 4 and 5 are provided, and these partitions 4 and 5 are provided.
The central portion of the region sandwiched between the two ends is partitioned by a pair of rectifying walls 6, 6, and a contact material such as gravel is filled between the rectifying walls 6, 6 to form a permeable biofilm contact region. 7 is formed, and the bag body 10 (expandable material) is submerged in one of the two regions 8 and 9 in the closed water body 3 separated by the biofilm contact region 7. Provided,
An opening 11 communicating with the surrounding sea area 2 is provided on the outer wall 1 that partitions one of the areas 8 from the surrounding sea area 2, and the bag body 10 is connected to the opening 11. is there.

The rectifying wall 6 is provided with a biofilm contact area 7 for contact material such as gravel.
And a plurality of water passage holes 12 for allowing water in each of the regions 8 and 9 on both sides thereof to flow into and out of the biofilm contact region 7 to effectively pass through the biofilm contact region 7. It is made of, for example, a concrete wall having an appropriate number of water holes 12 formed at an appropriate location, or a mesh member having a mesh such as a wire mesh.

The biofilm contact region 7 may be, for example, a region that performs biological excess, but generally, the concept of biological excess means literally excess, and is filled with a material having a specific surface area of 70 m ² / m ³ or more. It is considered something. However, in the case of the biofilm contact area 7 used here, it is necessary not only to purify the passing water but also to reduce the pressure loss when the water passes as much as possible. It is better to use a contact material used for catalytic oxidation. Examples of such a contact material include, in addition to the above-mentioned gravel, an anti-firestone, an oyster shell or a crushed material thereof, a molded article obtained by molding ceramics or the like into a lump or granule of an appropriate size, plastic, or the like. Is formed into a shape having a large specific surface area (for example, a shape in which one or a plurality of holes are formed in a hollow sphere). When the biofilm contact region 7 is formed by appropriately selecting such a contact material, it is necessary to consider clogging when the water passes through, and therefore, water having a high degree of contamination is purified. In this case, the specific surface area should be small (20-60 m ² / m ³ ), and when purifying relatively low polluted water, the specific surface area should be large (60 m ² / m ³ ).
m ² / m ³ or more). When the biofilm contact area 7 is configured, the rectifying walls 6 and 6
The start and end of the neighborhood are made of coarse materials,
In addition, by forming the central portion between the fine portions, it may be possible to devise so as to reduce the pressure loss as a whole. In this case, for example, the internal production of the biofilm contact region 7 increases in summer or the like. In this case, clogging can be prevented and sufficient purification performance can be ensured.

The bag body 10 is made of, for example, a seawater-resistant film material such as polyvinyl chloride or polyethylene rubber, but the tensile force and the compressive force applied to the bag body 10 are extremely small. In addition, since the internal pressure and the external pressure of the bag body 10 are very small, they may be made of any film material. The size (inner volume) of the bag 10 is determined by the distance between the surrounding sea area 2 and the closed water area 3 so that the bag body 10 does not expand to the maximum even when the surrounding sea area 2 is in spring tide. It is set to an appropriate size according to the maximum water level difference between them.

Next, the operation of the water purification equipment for closed water areas will be described with reference to FIGS.

As shown in FIG. 2, when the water level of the surrounding sea area 2 rises due to the rising tide from low tide to high tide, a water level difference occurs between the surrounding sea area 2 and the closed water area 3, and the water level increases. The potential energy due to the difference causes a flow of seawater from the surrounding sea area 2 to the closed water area 3 through the opening 11, whereby seawater in the surrounding sea area 2 is introduced into the bag body 10 through the opening 11. The Rukoto. When seawater is introduced into the bag body 10 in this manner, the water level of the region 8 in the closed water body 3 rises, and a water level difference occurs between the region 8 and the biofilm contact region 7. At the same time, due to the difference in water level, the water in the area 8 flows into the biofilm contact area 7 and the water level in the biofilm contact area 7 rises, whereby the biofilm contact area 7 and the biofilm contact area 7 A water level difference is generated between the area 8 and the opposite area 9 isolated from the area 8, and the water level difference causes water in the biofilm contact area 7 to flow out to the area 9 and the water level in the area 9 to rise. It will be. Actually, the water level difference between the areas 8, 7, 9 is not so remarkable as shown in FIG. 2 and is slight, and the water level of the areas 8, 7, 9 is small due to the slight water conveyance gradient. It rises at the same time. In this case, the water passing through the biofilm contact area 7 passes while maintaining an appropriate contact speed with the microorganism membrane adhered and immobilized on the surface of the contact material in the biofilm contact area 7. As a result, the microorganisms are effectively purified by the organic matter decomposing action. Then, in this way, as shown in FIG.
At high tide, the water levels of all the areas 8, 7, 9 in the closed water area 3 rise to the same water level as the water level of the surrounding sea area 2.

Further, as shown in FIG. 4, when the water level of the surrounding sea area 2 is lowered due to ebb tide from high tide to low tide, a water level difference occurs between the surrounding sea area 2 and the closed water area 3, and the water level is reduced. The potential energy due to the difference causes a flow of seawater from the closed water area 3 through the opening 11 to the surrounding sea area 2, whereby the bag provided in the closed water area 3 is formed.
The seawater inside 10 flows out to the surrounding sea area 2 through the opening 11. When the seawater inside the bag body 10 flows into the surrounding sea area 2 in this manner, the water level of the area 8 in the closed water area 3 falls, and the area 8 and the biofilm contact area 7
At the same time, the water level of the biofilm contact area 7 falls due to the flow of water in the biofilm contact area 7 into the area 8 due to the water level difference, whereby the biofilm contact area 7 And the biofilm contact area 7 and the area 8
Water level difference between the opposite area 9 isolated from the
Further, the water level difference causes the water in the area 9 to flow into the biofilm contact area 7 and the water level in the area 9 also decreases. Actually, the water level difference between the areas 8, 7, 9 is not so remarkable as shown in FIG. 4 and is slight, and the water level of the areas 8, 7, 9 is almost simultaneously due to the slight gradient of water conveyance. Going up. Also in this case, the water passing through the biofilm contact area 7 passes while maintaining an appropriate contact speed with the microorganism membrane adhered and immobilized on the surface of the contact material in the biofilm contact area 7. As a result, the microorganisms are effectively purified by the action of decomposing organic substances. Then, as shown in FIG. 5, when the surrounding sea area 2 becomes low tide, the water levels of all the areas 8, 7, and 9 in the closed water area 3 are the same as the water level of the surrounding sea area 2. It will fall to the water level.

As described above, in this closed water body water purification equipment, the water permeable biofilm contact area that separates the closed water body 3 into the two regions 8 and 9 in the closed water body 3 closed from the surrounding sea area 2. 7 and an opening 11 communicating with the surrounding sea area 2 is provided in one area 8, and in the area 8, the opening 11 is connected to the opening 11 according to the amount of seawater introduced from the surrounding sea area 2. Since the bag body 10 that changes in volume is provided in a submerged state, the tidal force of the surrounding sea area 2 can generate flow energy in the closed water area 3, and the flow energy can generate water in the closed water area 3. Can flow through the biofilm contact area 7. At this time, the water passing through the biofilm contact area 7 is maintained at a proper speed by maintaining the contact speed between the microbial membrane adhered and immobilized on the contact material in the biofilm contact area 7 and the water at an appropriate speed. It can be purified by the organic matter decomposition action of the membrane.

In addition, in this water purification system for closed water areas, openings are provided as necessary so as not to be affected by the wave power of the surrounding sea area 2.
A breakwater or the like may be provided in the surrounding sea area 2 around the area 11, and it is even better if various measures are taken in case of emergency such as when a tsunami occurs.

 FIG. 6 is a view showing a second embodiment of the present invention.

The water purification equipment of the closed water area of this embodiment has the same configuration as the water purification equipment of the first embodiment. However, in this water purification equipment, the biofilm contact area 7 in the closed water area 3 is used. The bag body 10 is not provided in the one area 8 isolated by the above, and instead, a serpentine-shaped expansion / contraction material 13 made of a plastic material or the like is provided.

In this water purification facility, the tidal force of the surrounding sea area 2 is used to allow seawater in the surrounding sea area 2 to flow into and out of the expansion / contraction member 13, thereby raising and lowering the water level in the area 8. Thus, the water in the closed water area 3 is caused to flow and pass through the biofilm contact area 7, whereby the microorganisms can be effectively purified by the organic matter decomposition action.

In addition, in the water purification equipment for closed water bodies of each of the embodiments, even if any of seawater, brackish water, and freshwater is stored in the closed water body 3, the water can be effectively purified. Can be. In other words, the water purification equipment for closed water areas can purify ponds, reservoirs, tides, canals, or various similar freshwater areas, brackish water areas, and seawater areas.

Further, when it is necessary to store water having the same composition as seawater in the closed water area 3 as described above, the seawater in the closed water area 3 is diluted by rainwater and the salt concentration gradually decreases. Therefore, in order to maintain the same composition as seawater, it is necessary to replace the water in the closed water area 3 with the seawater in the surrounding sea area 2 to some extent. In that case, one or more sluices are provided on the outer wall 1 separating the closed water area 3 and the surrounding sea area 2, and the sluice gate is opened and closed at an appropriate time so that the seawater in the surrounding sea area 2 is closed. 3 may be replaced by an appropriate amount.

Further, in each of the above embodiments, the case where the surrounding water area 2 is a sea area has been described. However, such a water purification system for a closed water area includes, in addition to the vicinity of sea areas such as a bay, a bay, and a port,
For example, it may be provided in the vicinity of various brackish water areas or freshwater areas having water level fluctuations such as lakes and marshes communicating with the sea area,
Even in such a case, it is possible to sufficiently purify the water quality using the fluctuation of the water level in the water area.

"Evaluation of purification performance" As an example of the water purification equipment for closed water areas of the present invention,
A water purification facility was provided in the closed water area 3 as shown in FIG. In FIG. 7, reference numeral 1 denotes an outer wall, 4 and 5 denote partition walls, 6 denotes a rectifying wall, 7 denotes a biofilm contact area, 8 and 9 denote respective areas separated by the biofilm contact area 7, 10 denotes a bag, 11 is an opening.

The closed water body 3 provided with this water purification facility is 10
It is formed in a rectangular shape of 0 m and 1000 m in width, and its depth is 2.5 m on average, with the tidal difference in the surrounding sea area as 1 m (2 to 3 m
Varies between).

Hereinafter, the purification performance of the water purification equipment in the closed water area 3 will be evaluated.

When evaluating the purification performance of such a water purification apparatus, what percentage of the water in the entire closed water area 3 is in the biofilm contact area 7.
, The linear velocity of water in the biofilm contact area 7, and the residence time in the biofilm contact area 7 are important. Therefore, each of these three points will be evaluated.

The area of the closed water area 3 is vertical (100m) x the horizontal (1000m) = 100,000m ² The average water volume in the closed water area 3 is the area of the closed water area 3 x the water depth = 250,000m ³ The amount of seawater that flows, that is, the amount of moving water in the closed water area 3 is, in one tide, the average amount of water x the tidal difference = 100,000 m ³ (Thus, the bag 10 has an inner volume of 100,000 m ³ or more. what it is understood that necessary.) that is, the amount of water moving to a day closed water 3, since the tide is twice a day, to be 100,000m ³ × 2 = 200,000m ³ Recognize.

Therefore, the ratio of the amount of water passing through the biofilm contact area 7 to the average amount of water in the entire closed water area 3 is the amount of water moving per day ÷ the average water amount × 100 = 80%. It can be seen that almost all of the water passes through the biofilm contact area 7 in one day.

Further, assuming that the filling height of the biological excess region 7 is 1.5 m, the cross-sectional area of the biological film contacting region 7 is 25 m × 1.5 m = 37.5 m ² .

Therefore, the linear velocity of water passing through the biofilm contact area 7 is determined by the following equation:
Since it is ^{200,000m 3, 200,000m 3 ÷ (24} × 60 × 60) is ÷ 37.5 m ² = 0.062 i.e. per second 6.2 cm, the linear velocity is sufficient for the contact rate between the biofilm contact material surface Speed.

Further, assuming that the length of the biofilm contact area 7 is 900 m, the volume of the biofilm contact area 7 is 37.5 m ² × 900 m = 33750 m ^3.
Since 8333 m ² (200,000 m ³ ÷ 24 = 8333 m ³ ) of water pass through, the residence time in the biofilm contact area 7 is 33750 m ³ ÷ 8333 m ³ = 4 (hours). 7 that a sufficient residence time can be obtained.

[Effects of the Invention] According to the water purification system for closed water bodies of the present invention, a water permeable biofilm contact area for isolating the closed water area into a plurality of areas is provided in the closed water area closed from the surrounding water area. Provided,
And, in at least one of the regions, an opening communicating with the surrounding water area is provided, and in the region,
Because the expanding and contracting material that is connected to the opening and changes in volume according to the amount of water introduced from the surrounding water area is provided in a submerged state,
As described below, flow energy can be generated in the closed water area by the tidal force of the surrounding water area, and the flow energy can cause the water in the closed water area to flow and pass through the biofilm contact area. it can. At that time, the water passing through the biofilm contact area is effectively decomposed by the organic matter decomposition action of the microbial membrane by maintaining the contact speed between the microorganism membrane immobilized in the biofilm contact area and the water at an appropriate speed. It can be purified.

That is, when the water level of the surrounding water area rises due to rising tide from low tide to high tide, a water level difference occurs between the surrounding water area and the closed water area, and the potential energy due to the water level difference causes an opening from the surrounding water area. A flow of water through the section towards the closed body of water occurs, thereby causing water in the surrounding body of water to pass through the opening and into the interior of the expansion and contraction material. For this reason, it is possible to raise the water level in the area where the expanding and contracting material is provided in the closed water area to cause a water level difference between the area and the biofilm contact area. The water level of the biofilm contact area can be raised by flowing the water of the area into the biofilm contact area, whereby the biofilm contact area and the opposite side isolated from the biofilm contact area by the biofilm contact area A water level difference can be caused between the above-mentioned region and the water level difference, and the water in the biofilm contact region can be caused to flow out to the region on the opposite side of the above-mentioned region to raise the water level in that region. In this case, the water passing through the biofilm contact area is allowed to pass through while maintaining an appropriate contact speed with the microbial membrane immobilized in the biofilm contact area, thereby decomposing the organic substance of the microbial membrane. It can be more effectively purified. Then, in this way, when the surrounding water area becomes high tide, the water levels of all the areas in the closed water area can be raised to the same water level as the surrounding water area.

Also, when the water level in the surrounding water area falls due to ebb tide from high tide to low tide, there is a water level difference between the surrounding water area and the closed water area, and the potential energy due to the water level difference causes the water to open from the closed water area. A flow of water is generated toward the surrounding water body through the portion, whereby water inside the expanding / contracting material provided in the closed water body flows through the opening to the surrounding water body. For this reason, it is possible to lower the water level of the area in which the expandable material is provided in the closed water area to cause a water level difference between the area and the biofilm contact area, and at the same time, by the water level difference, The water in the biofilm contact area can be lowered by flowing the water in the biofilm contact area into the area, whereby the biofilm contact area and the opposite side isolated from the area by the biofilm contact area A water level difference can be generated between the above-mentioned region and the water level difference, and the water in the region opposite to the above-mentioned region can flow into the biofilm contact region to raise the water level in that region. Also in this case, the water passing through the biofilm contact area is allowed to pass while maintaining a high contact speed with the microbial membrane immobilized in the biofilm contact area. Purification can be effectively performed by the decomposition action. Then, in this way, when the surrounding water area becomes low tide, the water levels of all the areas in the closed water area can be lowered to the same water level as the surrounding water area.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 5 are diagrams showing a water purification system for closed water bodies according to a first embodiment of the present invention, wherein FIG. 1 is a plan view and FIG. 2 is a rising tide. 3 is a cross-sectional view of a main part showing a state at high tide, FIG. 4 is a cross-sectional view of a main part showing a state of ebb tide, and FIG. 5 is a state at a low tide. It is sectional drawing of the principal part shown. FIG. 6 is a sectional view of a main part of a water purification system for closed water bodies according to a second embodiment of the present invention. FIG. 7 is a plan view used for evaluating the purification performance of the water purification equipment for closed water areas of the present invention. 1 ... outer wall, 2 ... surrounding water area, 3 ... closed water area, 4, 5 ... partition wall, 6 ... rectifying wall, 7 ... biofilm contact area, 8, 9 ... isolated by biofilm contact area Area, 10 …… Expansion material (bag), 11… Opening, 12… Water hole.

Claims (1)

(57) [Claims] 1. A closed water body closed from a surrounding water body,
A permeable biofilm contact area that isolates the closed water area into a plurality of areas is provided, and in at least one of the areas, an opening communicating with the peripheral water area is provided, and the area is provided. A water purifying apparatus for a closed water body, wherein an expanding / contracting material connected to the opening and changing in volume in accordance with the amount of water introduced from the surrounding water area is provided in a submerged state.